Can regular emergency exits not work after crashlanding?
All regular exits are generally used in an emergency. This information would be included on the safety card and in the briefing by the crew before the flight.

Of course, during a crash, structure can deform and exits can become blocked. Regulations require evacuation within time limits using only half of the available exits. This must be demonstrated to be possible.

Here is a Q400 safety card, showing that two forward and two aft exits are used for evacuation. The forward right exit (called R1) is an emergency exit.


Source