It's much easier to be deliberative about deciding to evacuate when you have two cockpit exits and the front exit doors directly behind you.
In the back with your wife and kids ten rows away from the nearest exit with sixty odd panicked sheep focussed on retrieving their considerable cabin baggage blocking the way, the atmosphere is heavily biased against calm deliberation.
There was a 737 that blew an engine and aborted takeoff in CYYC many years ago. The pax popped the slides while the crew were discussing with the tower -- and got out in the nick of time.