diff --git a/packages/engine/src/game.ts b/packages/engine/src/game.ts
index f772a6d..fcef469 100644
--- a/packages/engine/src/game.ts
+++ b/packages/engine/src/game.ts
@@ -205,6 +205,8 @@ export interface CastParams {
   clockwise?: boolean;
   /** MEGA-MONSTER: which stat doubles. */
   boost?: "life" | "movement";
+  /** PICK LOCK / MASTER KEY: hold the door open for others. */
+  hold?: boolean;
 }
 
 export interface GameConfig {
@@ -250,6 +252,10 @@ export interface GameState {
   doorStates: Record<string, "jammed" | "removed">;
   /** Door edges unlocked until the end of the current turn. */
   openDoorEdges: string[];
+  /** Doors physically HELD open ("You may 'hold the door open' for others"
+   * — MASTER KEY, PICK LOCK): unlocked past end of turn, until the holder
+   * steps out of adjacency or falls. */
+  heldDoors: { key: string; by: PlayerId; cell: Cell; side: Side }[];
   /** Walls/firewalls conjured during play (dispellable), by edge key. */
   createdEdges: Record<string, true>;
   /** Square-filling creations, by cell key. */
@@ -573,6 +579,8 @@ export type GameEvent =
   | { type: "wallDestroyed"; caster: PlayerId; edge: { cell: Cell; side: Side }; wasDoor: boolean }
   | { type: "wallDamaged"; player: PlayerId; edge: { cell: Cell; side: Side }; amount: number; total: number; needed: number; source: string }
   | { type: "doorUnlocked"; player: PlayerId; edge: { cell: Cell; side: Side }; withCardId: string }
+  | { type: "doorHeld"; player: PlayerId; edge: { cell: Cell; side: Side } }
+  | { type: "doorReleased"; edge: { cell: Cell; side: Side } }
   | { type: "doorsRelocked"; count: number }
   | { type: "doorJammed"; player: PlayerId; edge: { cell: Cell; side: Side } }
   | { type: "lockRemoved"; player: PlayerId; edge: { cell: Cell; side: Side } }
@@ -2798,6 +2806,10 @@ function remapState(
   state.doorStates = remapRecord(state.doorStates, mapEdgeKey);
   state.illusionWalls = remapRecord(state.illusionWalls, mapEdgeKey);
   state.openDoorEdges = state.openDoorEdges.map(mapEdgeKey);
+  for (const h of state.heldDoors) {
+    h.key = mapEdgeKey(h.key);
+    if (inSector(h.cell)) h.cell = mapCell(h.cell);
+  }
   state.squareContents = remapRecord(state.squareContents, mapCellKey);
   state.slimeTraps = remapRecord(state.slimeTraps, mapCellKey);
   state.groundObjects = remapRecord(state.groundObjects, mapCellKey);
@@ -2967,9 +2979,27 @@ function unlockDoor(
   }
   if (!state.openDoorEdges.includes(key)) state.openDoorEdges.push(key);
   events.push({ type: "doorUnlocked", player: caster.id, edge: found, withCardId: cardId });
+  if (cmd.params?.hold) {
+    if (!state.heldDoors.some((h) => h.key === key)) {
+      state.heldDoors.push({ key, by: caster.id, cell: found.cell, side: found.side });
+    }
+    events.push({ type: "doorHeld", player: caster.id, edge: found });
+  }
   return null;
 }
 
+/** A held door needs its holder: standing adjacent and alive. Anything that
+ * moves or fells them — a step, a shove, a teleport, a killing blow — lets
+ * the door swing shut. */
+function sweepHeldDoors(state: GameState, events: GameEvent[]): void {
+  for (const h of [...state.heldDoors]) {
+    const holder = state.players.find((p) => p.id === h.by);
+    if (holder?.alive && isAdjacentToEdge(holder.position, h.cell, h.side)) continue;
+    state.heldDoors = state.heldDoors.filter((x) => x !== h);
+    events.push({ type: "doorReleased", edge: { cell: h.cell, side: h.side } });
+  }
+}
+
 function attachSustained(
   state: GameState,
   events: GameEvent[],
@@ -3131,6 +3161,7 @@ export function createGame(config: GameConfig): { state: GameState; events: Game
     chaosPending: null,
     doorStates: {},
     openDoorEdges: [],
+    heldDoors: [],
     createdEdges: {},
     squareContents: {},
     groundObjects: {},
@@ -3191,6 +3222,12 @@ export function createGame(config: GameConfig): { state: GameState; events: Game
 // Command application
 
 export function applyCommand(state: GameState, playerId: PlayerId, command: Command): CommandResult {
+  const result = applyCommandInner(state, playerId, command);
+  if (result.ok) sweepHeldDoors(result.state, result.events);
+  return result;
+}
+
+function applyCommandInner(state: GameState, playerId: PlayerId, command: Command): CommandResult {
   if (state.phase !== "playing") return err("game is over");
 
   if (state.pendingDiscard) {
@@ -3439,7 +3476,8 @@ function doMove(prev: GameState, direction: Side, over = false): CommandResult {
       if (isBlinded(state, p)) return blindBump(state, events, p, direction);
       return err("blocked");
     }
-    if (edge === "door" && (state.doorStates[key] === "removed" || state.openDoorEdges.includes(key))) {
+    if (edge === "door" && (state.doorStates[key] === "removed" || state.openDoorEdges.includes(key) ||
+        state.heldDoors.some((h) => h.key === key))) {
       p.position = dest;
       via = "step";
     } else if (edge === "firewall") {
diff --git a/packages/engine/src/view.ts b/packages/engine/src/view.ts
index 666924e..54edb59 100644
--- a/packages/engine/src/view.ts
+++ b/packages/engine/src/view.ts
@@ -62,6 +62,8 @@ export interface GameView {
   /** Accumulated attack damage per edge (public — cracks show). */
   wallDamage: Record<string, number>;
   openDoorEdges: string[];
+  /** Door edges held open by a standing wizard. */
+  heldDoorEdges: string[];
   /** Illusion edges YOU know are fake (creator or saw through); others see walls. */
   knownIllusionEdges: string[];
   creatures: CreatureState[];
@@ -137,6 +139,7 @@ export function viewFor(state: GameState, playerId: PlayerId): GameView {
     doorStates: { ...state.doorStates },
     wallDamage: { ...state.wallDamage },
     openDoorEdges: [...state.openDoorEdges],
+    heldDoorEdges: state.heldDoors.map((h) => h.key),
     knownIllusionEdges,
     creatures: state.creatures.map((c) => ({ ...c, scorchedThisTurn: [...c.scorchedThisTurn] })),
     wandCharges: { ...state.wandCharges },
diff --git a/packages/engine/test/durations-doors-cards.test.ts b/packages/engine/test/durations-doors-cards.test.ts
index bbab4ae..b88b89c 100644
--- a/packages/engine/test/durations-doors-cards.test.ts
+++ b/packages/engine/test/durations-doors-cards.test.ts
@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { applyCommand, activePlayer, boardView, sustainedOn, type GameState } from "../src/game";
+import { applyCommand, activePlayer, boardView, createGame, sustainedOn, type GameState } from "../src/game";
 import { cellKey, edgeKey, neighbor, type Side } from "../src/board";
 import type { CardInstance } from "../src/cards";
 import { newGame, must, giveCard, toRound2, faceOff, castAt } from "./helpers";
@@ -346,3 +346,66 @@ describe("cast modifiers", () => {
     expect(d.lostTurns).toBe(1); // the stun still applies
   });
 });
+
+describe("holding the door open (Pick Lock / Master Key)", () => {
+  function doorRig() {
+    let { state } = createGame({ playerIds: ["holder", "guest"], seed: 42, sets: ["basic"], deckRev: 14 });
+    state = toRound2(state);
+    // Find a door edge; stand the acting player beside it.
+    const view = boardView(state);
+    for (const [key, edge] of Object.entries(view.edges)) {
+      if (edge !== "door") continue;
+      const [kind, coords] = key.split(":") as [string, string];
+      const [x, y] = coords.split(",").map(Number) as [number, number];
+      const cell = { x, y };
+      const side = kind === "V" ? ("E" as Side) : ("S" as Side);
+      const holder = activePlayer(state);
+      holder.position = { ...cell };
+      return { state, key, cell, side, holder: holder.id };
+    }
+    throw new Error("setup: seed 42 grew a maze with no doors");
+  }
+
+  it("a held door outlives the turn and admits another wizard", () => {
+    let { state, key, cell, side, holder } = doorRig();
+    const pick = giveCard(state, holder, "pick-lock");
+    state = must(state, holder, {
+      type: "cast", instanceId: pick.instanceId,
+      target: { kind: "edge", cell, side }, params: { hold: true },
+    });
+    state = must(state, holder, { type: "endTurn", draw: 0 });
+    expect(state.heldDoors.some((h) => h.key === key)).toBe(true);
+    const guest = state.players.find((p) => p.id !== holder)!;
+    guest.position = { ...cell };
+    const r = applyCommand(state, guest.id, { type: "move", direction: side });
+    if (!r.ok) throw new Error(r.error);
+    const through = r.state.players.find((p) => p.id === guest.id)!;
+    expect(cellKey(through.position)).toBe(cellKey(neighbor(cell, side)));
+  });
+
+  it("the door swings shut the moment the holder steps away", () => {
+    let { state, key, cell, side, holder } = doorRig();
+    const pick = giveCard(state, holder, "pick-lock");
+    state = must(state, holder, {
+      type: "cast", instanceId: pick.instanceId,
+      target: { kind: "edge", cell, side }, params: { hold: true },
+    });
+    expect(state.heldDoors.some((h) => h.key === key)).toBe(true);
+    // March the holder until adjacency breaks; the sweep must release.
+    let walked = state;
+    let released = false;
+    const dirs: Side[] = ["N", "E", "S", "W"];
+    for (const d1 of dirs) {
+      const r1 = applyCommand(walked, holder, { type: "move", direction: d1 });
+      if (!r1.ok) continue;
+      if (!r1.state.heldDoors.some((h) => h.key === key)) { released = true; break; }
+      for (const d2 of dirs) {
+        const r2 = applyCommand(r1.state, holder, { type: "move", direction: d2 });
+        if (!r2.ok) continue;
+        if (!r2.state.heldDoors.some((h) => h.key === key)) { released = true; break; }
+      }
+      if (released) break;
+    }
+    expect(released).toBe(true);
+  });
+});
diff --git a/packages/web/src/App.svelte b/packages/web/src/App.svelte
index 407b099..4936105 100644
--- a/packages/web/src/App.svelte
+++ b/packages/web/src/App.svelte
@@ -128,6 +128,8 @@
   let tradeFrom = $state<{ x: number; y: number } | null>(null);
   /** rotate-sector direction. */
   let rotateCW = $state(true);
+  /** pick-lock / master-key: prop the door for others once it opens. */
+  let holdDoor = $state(false);
   /** mega-monster: which stat the chosen monster doubles. */
   let megaBoost = $state<"life" | "movement">("life");
   /** teleport: the marked destination awaiting its confirming second tap. */
@@ -300,6 +302,7 @@
     selectedCreature = null;
     selectedCard = null;
     megaBoost = "life";
+    holdDoor = false;
     pendingTeleport = null;
     attachedNumber = null;
     attachedMods = [];
@@ -713,6 +716,8 @@
       type: "cast",
       instanceId: selectedCard.instanceId,
       target: { kind: "edge", cell, side },
+      ...(holdDoor && (selectedCard.cardId === "pick-lock" || selectedCard.cardId === "master-key")
+        ? { params: { hold: true } } : {}),
       ...(attachedNumber ? { numberInstanceIds: [attachedNumber.instanceId] } : {}),
     });
     clearSelection();
@@ -1550,6 +1555,9 @@
                 onclick={() => (megaBoost = "movement")}>movement</button>
               <span>— then tap the monster</span>
             {/if}
+            {#if selectedCard?.cardId === "pick-lock" || selectedCard?.cardId === "master-key"}
+              <label class="inline"><input type="checkbox" bind:checked={holdDoor} /> hold the door open</label>
+            {/if}
             {#if selectedCard?.cardId === "rotate-sector"}
               <label class="inline"><input type="checkbox" bind:checked={rotateCW} /> clockwise</label>
               <span>— click the sector</span>
diff --git a/packages/web/src/Board.svelte b/packages/web/src/Board.svelte
index 3c1d714..45a0e26 100644
--- a/packages/web/src/Board.svelte
+++ b/packages/web/src/Board.svelte
@@ -130,7 +130,9 @@
         // A door's lock can be gone for good, jammed shut, or picked open
         // for the turn — each earns its own look.
         const lock = state === "door"
-          ? (view.doorStates[key] ?? (view.openDoorEdges.includes(key) ? "ajar" : null))
+          ? (view.doorStates[key] ??
+             (view.heldDoorEdges.includes(key) ? "held"
+              : view.openDoorEdges.includes(key) ? "ajar" : null))
           : null;
         return { kind, x, y, state, lock };
       }),
@@ -363,6 +365,7 @@
     {@const cls = e.state === "door" ? `door${e.lock ? ` ${e.lock}` : ""}` : e.state === "firewall" ? "firewall" : "wall"}
     {@const lockTitle = e.lock === "removed" ? "lock removed — swings free"
       : e.lock === "jammed" ? "lock jammed — sealed for good"
+      : e.lock === "held" ? "held open by a standing wizard"
       : e.lock === "ajar" ? "unlocked until end of turn" : null}
     {#if e.kind === "V"}
       <rect
@@ -635,6 +638,8 @@
   .door.jammed { fill: #3a2a18; stroke: #14100b; }
   /* Picked or keyed open until end of turn. */
   .door.ajar { fill: #d4bd8e; stroke-dasharray: 5 3; }
+  /* Held open: a wizard stands propping it. */
+  .door.held { fill: #d4bd8e; stroke: #2e7d32; }
   .firewall {
     fill: #d0342c;
     stroke: #7c1a14;
diff --git a/packages/web/src/net.svelte.ts b/packages/web/src/net.svelte.ts
index c545010..78d8ed4 100644
--- a/packages/web/src/net.svelte.ts
+++ b/packages/web/src/net.svelte.ts
@@ -74,6 +74,8 @@ export function humanize(e: GameEvent): string | null {
     case "cardsStolen": return `${e.to} steals ${e.count} card(s) from ${e.from}'s thoughts!`;
     case "handRevealed": return `${e.to} reads ${e.player}'s mind — their hand is revealed.`;
     case "doorUnlocked": return `${e.player} unlocks a door.`;
+    case "doorHeld": return `${e.player} holds the door open.`;
+    case "doorReleased": return `The held door swings shut.`;
     case "doorsRelocked": return `The door swings shut and relocks.`;
     case "doorJammed": return `${e.player} jams a door's lock solid.`;
     case "lockRemoved": return `${e.player} removes a door's lock for good.`;