[suggestion] Improve pathing logic

[eslader]

I've been wrestling with the problem of guards leaving the door control console and permanently disabling the doors. Here's what's happening:

When the guard leaves the console, the game picks a free guard to take over for him. But if that guard's most direct path to the console includes a remote door, he can't get through it. The game does not reassign console duty to anyone else, and the guard ignores alternate paths that would not pass through a remote door.

If the game chose the most direct path, and then verified that the path was actually passable, and then chose a different path if it was not, this wouldn't happen.

Alternately, if the guard leaving the console had to wait until his replacement got there, this would eliminate the problem as well, while also being more realistic.