Police cars and deadlocks - dentine
The crash 2 days ago in N Ireland where four police died has had a fair bit of publicity.The bare facts are bad enough, but I caught the NI local news broadcast last night and it seems the actual circumstances are worse... the four policemen were conscious after the impact and were trying to get out of the vehicle but couldn't open the doors, and a dozen bystanders were trying to get in through the windows but couldn't break the glass.

The four succumbed to flames.

My question is: are Police vehicles fitted with particular deadlocks to stop the doors being opened from the inside? (by a suspect in the rear seat for example). And are the windows bullet-proof?

My own understanding of door locks is that they should all have a "fail-safe" arrangement whereby all locks are opened following a high-impact crash.
Police cars and deadlocks - Mr X
Police cars nearly always have the ' child locks on " on the rear doors so as to stop the doors being opened from inside and the back seat occupants escaping. Can't see why they would not have opened from the outside though.
Police cars and deadlocks - TheOilBurner
That sounds just awful. I can only imagine that the doors must have been wedged shut from the accident.
Police cars and deadlocks - Chris S
So all four doors wouldn't open? Sounds a bit implausible to me.

And the PSNI carry guns, they'd be able to shoot out a window as a last resort.

There's no point in having bullet-proof glass in the car if the rest of the vehicle isn't.