People have a predisposition to a type of power (administrator, in T's case), and then the nature of the trigger event defines the specifics (trapped in a trash-filled locker > bugs).
For another example, Tattletale, Dinah, and Contessa are all observer-types and could have developed identical powers. Tattletale's trauma was being blamed for not knowing her brother was going to kill himself, and the resultant power is super-educated guessing, near omnipotence if she has any context on a subject.
Dinah triggered when her school was attacked by a cape, and her power is predicting the odds of any future event, especially a casualty event, with decimal accuracy.
Contessa triggered when trapped in an inevitable-death scenario, and her power is 'seeing the path to victory,' which is very similar to Dinah's but focused on actions, not odds.
(cw: mentions of suicide in a peripheral character)