Mike,
Safety demo usually done during pushback/engine start. The only information we are giving them at the point that will be useful in a ground fire is the location of exits. In the event of a fire before/during the demo they will become very clear with crew screaming from them for pax to come towards them, along with the emergency lighting .
On taxi in, crew are by the doors after they are disarmed. In the event something were to go wrong, the doors can still be quickly armed and opened. The seatbelt light is not swicthed off until engines are shutdown, therefore pax should not be up/in overhead lockers etc until after the threat of fire has all but ceased.