I was on a BA 777 that had an emergency evacuation.
One of things that struck me afterwards was how peoples recollection of an incident can differ substantially even when they are in close proximity. As an example, how serious you thought the incident was depended on whether you were facing forward or back and which side of the aircraft you were on. Discussing it afterwards, in the row I was in the guy by the left hand window thought we were going to die, the guy next to me thought we were in big trouble and I (right hand window) thought I was going to be late for a meeting. All rational opinions based on what we experienced.
My colleague and I went out the same door, one behind the other. He recalls a stewardess shouting 'go, go, go' or something similar at the door. I have no recollection of seeing or hearing her.
Each of the posters above is relating what they recall - but recollection of events at times of high stress is not perfect and different people will have had very different experiences.
Oh - and if I saw smoke and sparks under my seat I think it highly likely that I would shout 'fire'. I need to get someone's attention, and fast.