No-one can say what they would do in that kind of situation,the only exception to the rule i would say would be military or ex-military and police.,otherwise i am certain that most here have never ever even experienced that kind of terror,and to witness what those people on that bus witnessed would of been horrific beyond belief - i bet there probably was by all probablities some handy blokes on that bus - and i bet they totaly crapped themselves.
to witness another person cut to pieces and to be placed in direct risk of the same being done to you would be totaly terrifying.
dis-arming someone doesnt come near it,let alone sneaking up behind someone with a bat and knocking them out.,so no-one here can say what they would do.,absolutely NO-ONE (unless there military or ex-military or police )