The good news is nothing serious hapenned.
The question is why do things like these (pax agression) happen ?
Let us look at a scenariowhere pax que up for a long time, going through check in, security, immigration, etc...
Pax take their seats, allowing for ground preparations, it will be quite some time before airborne.
Pilots leave seat belts sign for a long period of time, sometimes unnecesarilly.
Some airlines leave the signs up to 10 000ft,
Some time pilots just forget to switch them off ( I have done it myself)
While the signs are on usually the cabin crew do not want to "disturb" the flight deck (just to ckeck/remind),
In the mean time some poor pax with a weak bladder is desperate to go for a relief.
I have seen this happen to paxs(to myself on an occasion), and some cabin crew do not know how to handle this situation. They will quite correctly stop pax from moving about. The sad thing is they can do it without finesse, causing the already agravated pax to blow theifuses, and before you know it the whole thing is blown out propotion.
It is much worse if you are sitting in the economy section.