So, how I understand it is that our brains have something like a seizing threshold. Which is the amount of stress they can be put under before a seizure is induced. Certain things can lower that threshold. And I think caffeine (or stimulants in general?) and lack of sleep are both things that lower it.

So it was the loud music and bright strobe light that triggered the seizure. The caffeine and the lack of sleep lowered my brains resistance to seizing.