A previous poster on this thread, a builder by trade, pointed out that buildings when impacted tend to collapse in distinct stages, so an interval of time may take place between the first impact and when the materiels used in the construction have stretched or separated. A secondary collapse of the roof may then take place, as those in the bar reported.
Also, time experienced by observers may not feel the same as the actual minutes elapsed. I know that in case of a launch failure, time seems to slow down, you can do quite a lot in 30 seconds if you know what to do.