The fallback should work like the normal does. What you want, if things go wrong, is something that works as much like what you're used to as possible, so that you can recover easily.
The worst thing you can do, if things go wrong, is drop users into an unfamiliar environment that sends them scurrying around looking for the manuals.
The panic room should look just like the normal room, save it has a big sign that says "Don't Panic".
ron