diff --git a/src/server/components/aggro.js b/src/server/components/aggro.js
index 23a05e59..95e743aa 100644
--- a/src/server/components/aggro.js
+++ b/src/server/components/aggro.js
@@ -414,7 +414,7 @@ module.exports = {
 
 	setAllAmounts: function (amount) {
 		this.list.forEach(l => {
-			l.amount = amount;
+			l.threat = amount;
 		});
 	}
 };
diff --git a/src/server/security/connections.js b/src/server/security/connections.js
index 94771b05..b1d3bad6 100644
--- a/src/server/security/connections.js
+++ b/src/server/security/connections.js
@@ -25,7 +25,7 @@ module.exports = {
 		this.players.push(p);
 	},
 
-	onDisconnect: function (socket) {
+	onDisconnect: async function (socket) {
 		let player = this.players.find(p => p.socket.id === socket.id);
 
 		if (!player)
diff --git a/src/server/world/atlas.js b/src/server/world/atlas.js
index 113821a5..65290811 100644
--- a/src/server/world/atlas.js
+++ b/src/server/world/atlas.js
@@ -2,14 +2,13 @@
 const objects = require('../objects/objects');
 const events = require('../misc/events');
 const {
-	getThread, killThread, sendMessageToThread, getThreadFromId, returnWhenThreadsIdle
+	getThread, killThread, sendMessageToThread, getThreadFromId, returnWhenThreadsIdle, canThreadBeClosed
 } = require('./threadManager');
+const { registerCallback, removeCallback } = require('./atlas/registerCallback');
 
 //Exports
 module.exports = {
 	nextId: 0,
-	lastCallbackId: 0,
-	callbacks: [],
 
 	addObject: async function (obj, keepPos, transfer) {
 		const serverObj = objects.objects.find(o => o.id === obj.id);
@@ -80,7 +79,7 @@ module.exports = {
 			callback();
 	},
 
-	removeObject: function (obj, skipLocal, callback) {
+	removeObject: async function (obj, skipLocal, callback) {
 		if (!skipLocal)
 			objects.removeObject(obj);
 
@@ -88,7 +87,7 @@ module.exports = {
 		if (!thread)
 			return;
 
-		if (thread.instanced) {
+		if (thread.instanced && await canThreadBeClosed(thread, this.registerCallback.bind(this))) {
 			this.removeObjectFromInstancedZone(thread, obj, callback);
 
 			return;
@@ -147,15 +146,11 @@ module.exports = {
 	},
 
 	registerCallback: function (callback) {
-		this.callbacks.push({
-			id: ++this.lastCallbackId,
-			callback: callback
-		});
-
-		return this.lastCallbackId;
+		return registerCallback(callback);
 	},
+
 	resolveCallback: function (msg) {
-		let callback = this.callbacks.spliceFirstWhere(c => c.id === msg.msg.id);
+		const callback = removeCallback(msg.msg.id);
 		if (!callback)
 			return;
 
diff --git a/src/server/world/atlas/registerCallback.js b/src/server/world/atlas/registerCallback.js
new file mode 100644
index 00000000..34e7b2fd
--- /dev/null
+++ b/src/server/world/atlas/registerCallback.js
@@ -0,0 +1,22 @@
+let lastCallbackId = 0;
+const callbacks = [];
+
+const registerCallback = callback => {
+	callbacks.push({
+		id: ++lastCallbackId,
+		callback
+	});
+
+	return lastCallbackId;
+};
+
+const removeCallback = callbackId => {
+	const callback = callbacks.spliceFirstWhere(c => c.id === callbackId);
+
+	return callback;
+};
+
+module.exports = {
+	registerCallback,
+	removeCallback
+};
diff --git a/src/server/world/instancer.js b/src/server/world/instancer.js
index 8a505556..e6361560 100644
--- a/src/server/world/instancer.js
+++ b/src/server/world/instancer.js
@@ -385,6 +385,18 @@ module.exports = {
 				id: callbackId
 			}
 		});
-	}
+	},
 
+	getPlayerCount: function ({ callbackId }) {
+		process.send({
+			module: 'atlas',
+			method: 'resolveCallback',
+			msg: {
+				id: callbackId,
+				result: {
+					playerCount: objects.objects.filter(o => o.player !== undefined).length
+				}
+			}
+		});
+	}
 };
diff --git a/src/server/world/threadManager.js b/src/server/world/threadManager.js
index 95bdb71f..bcb05b48 100644
--- a/src/server/world/threadManager.js
+++ b/src/server/world/threadManager.js
@@ -5,6 +5,7 @@ const childProcess = require('child_process');
 const objects = require('../objects/objects');
 const connections = require('../security/connections');
 const { mapList } = require('./mapManager');
+const { registerCallback } = require('./atlas/registerCallback');
 
 //Internals
 const threads = [];
@@ -19,6 +20,21 @@ const getThreadFromId = threadId => {
 	return threads.find(t => t.id === threadId);
 };
 
+const canThreadBeClosed = async thread => {
+	const { playerCount } = await new Promise(res => {
+		const cb = registerCallback(res);
+
+		thread.worker.send({
+			method: 'getPlayerCount',
+			args: {
+				callbackId: cb
+			}
+		});
+	});
+
+	return playerCount === 0;
+};
+
 const messageHandlers = {
 	onReady: function (thread) {
 		thread.worker.send({
@@ -78,7 +94,7 @@ const messageHandlers = {
 	rezone: async function (thread, message) {
 		const { args: { obj, newZone, keepPos = true } } = message;
 
-		if (thread.instanced) {
+		if (thread.instanced && await canThreadBeClosed(thread)) {
 			thread.worker.kill();
 			threads.spliceWhere(t => t === thread);
 		}
@@ -242,5 +258,6 @@ module.exports = {
 	spawnMapThreads,
 	messageAllThreads,
 	sendMessageToThread,
-	returnWhenThreadsIdle
+	returnWhenThreadsIdle,
+	canThreadBeClosed
 };