Ew! I remember the bus rides from elementry and middle school! Some of the worst (and actually some of the FUNNIEST) rides of my life were on the "Big Cheese" XD
I'm sorry, I totally get that awkwardness when you get ditched. I understand. Maybe just try and tell Penny how that made you feel.
Okay, how would you get expelled or suspended? If anything, the school would be in trouble for your injury, and that's unlikely (because of your permission slips and liability doesn't land on the school or the theater). Honestly, it probably won't even be addressed, so I wouldn't even give it a second thought!
:)