Fix 8688 - AIs getting disconnected when accessing the same shell/cyb…

…org (goonstation#13613)

code/datums/mind.dm

@@ -82,11 +82,21 @@ datum/mind
 				message_admins("Tried to transfer mind of mob [current] (\ref[current], [key_name(current)]) to qdel'd mob [new_character] (\ref[new_character]) God damnit. Un-qdeling the mob and praying (this will probably fuck up).")
 				new_character.disposed = 0
 			else
-				message_admins("Tried to transfer mind [src] (\ref[src]) to qdel'd mob [new_character] (\ref[new_character]) FIX THIS SHIT")
+				message_admins("Tried to transfer mind [src] to qdel'd mob [new_character] (\ref[new_character]).")
 
-			Z_LOG_ERROR("Mind/TransferTo", "Trying to transfer to a mob that's in the delete queue! Jesus fucking christ.")
+			Z_LOG_ERROR("Mind/TransferTo", "Tried to transfer mind [(current ? "of mob " + key_name(current) : src)] to qdel'd mob [new_character].")
+			return
 			//CRASH("Trying to transfer to a mob that's in the delete queue!")
 
+		if (new_character.client)
+			if (current)
+				boutput(current, "You were about to be transferred into another body, but that body was occupied!")
+				message_admins("Tried to transfer mind of mob [current] (\ref[current], [key_name(current)]) to mob with an existing client [new_character] (\ref[new_character])")
+			else
+				message_admins("Tried to transfer mind [src] to mob with an existing client [new_character] (\ref[new_character]).")
+			Z_LOG_ERROR("Mind/TransferTo", "Tried to transfer mind [(current ? "of mob " + key_name(current) : src)] to mob with an existing client [new_character] [key_name(new_character)])")
+			return
+
 		if (current)
 			if(current.client)
 				current.removeOverlaysClient(current.client)