'Rapid disembarkation'
As in via whatever doorway is in use and along the jetway or down the stairs?
I'm a volunteer fireman in my off hours. I'm also a Brit; I remember Hillsborough and I'm almost old enough to remember Ibrox. I know about fire, I know how people behave, and I know about panic.
I don't know for sure what studies have been carried out, but IF the pax panic I would imagine the potential for an absolutely lethal crush to develop at that single door would be very high indeed. I could easily see that… just one pax tripping could lead to a pileup, multiple fatalities through crushing, and a door blocked with bodies of the dead and dying - just from crush injuries, even if the fire itself is a bit of a non-event.
With due allowance for panic in a situation where there is a real known fire, even if it doesn't initially involve the cabin directly, I suspect a full evac via slides may always be the safer option.
I'd sooner find myself having to explain a couple of twisted ankles than a bunch of dead pax…