Well I was on A pvp server in the middle of a pvp battle and the out of no where I crashed this has happened many times and it makes me angry Please Help

Put the summary of the bug you're having here

What I expected to happen was...:
It would not crash and I would continue

What actually happened was...:
One click and boom a crash

Steps to Reproduce:
1. Get in A big pvp battle
2. have mcmmo
3. use the mcmmo and fight then just keep going and after a couple of more people set of the fireworks with pvp it crashes