I understand that the evac may have started before the pilots commanded it. Indeed we do not yet know whether the pilots were even contemplating evacuation before it was forced from the cabin. But that is not my question. My question is only whether the 40+ second delay from stopping to engine spool down is: (a) representative of a situation on the flight deck where preparation for an evac was being performed as fast as possible given the checklists; or (b) representative of a situation that was not initially pointing to an immediate evac?
Another way to put it is as follows: what is the minimum time from a plane stopping to when an evac can begin (without running engines interfering with slides) assuming all the checklist items begun immediately and are executed without difficulty? Is this possible within 20 seconds? Or does it take 40+ seconds? If the former, it would appear that there was some delay in commencing or difficulty in performing the checklists. If the latter, then everything went as expected -- other than for the slides being deployed too soon.
Again, I don't what the correct answer is, and I certainly am unwilling to say that any mistakes are made. Because this incident is the subject of an NTSB investigation, we certainly will learn what actually occurred. But on PPRuNe, we always try to jump the gun and figure things out in advance of getting all of the facts.