Total hunch here.. ( see if I am proven to be psychic, or psycho)....
In watching the interview with the cab driver, here is what I felt/saw...
He kept mentioning about locking the door, especially with students, until people paid..and not having 20 cents change to give them.
If you're gonna rob/assault someone, you don't pay them first?
So here's my theory, putting myself on the line here, and total conjecture, but.. hey.. what the heck..
I think the cab driver must have said something to piss them off, so they paid him 15 bucks and probably demanded their 20 cents back, ie.. no tip. The cabbie said he didn't have 20 cents.. and probably didn't unlock the door to let them out, so that's why they probably grabbed the guy, hit, whatever, to get him to let them out.
Either that or he wasn't happy with the 20 cent tip, and tried to extort more by not letting them out.
if this is true, then it makes sense that they would say.. " You don't know who you are messing with..." That whole phrase, " messing with", doesn't make sense otherwise... " you don't know who you are messing with"... that implies the cabbie was messing with them, so either he tried to cheat them, or wouldn't let them out..
This is supported by the fact that Kane is pleading not guilty..
okay.. there.. let's see if I am close... or nuts