You prepare the A/C for evacuation anytime that ther is a potential threat, you assess the situation and only then you call for the evacuation.
An evacuation is a risky situation which can lead to injuries, so if the danger is cleared it is much wiser to wait for the stairs and disembark through the doors.
ASs said one of the items of the C/L is to retract the spoilers if not I would not try to go through the overwing hatches.... unless you are a steeple chase specialist.
