Having to figure out how to navigate the spider powers as a grown ass man and how to hide it from people— specifically Kingpin.
Miles, for whatever reason, still goes down to the subway tunnel— maybe just to brood, or add more to the walls— and that’s when he sees the fight. And being a normal regular ass teenager, he doesn’t have the strength yet to barely survive just watching the battle ongoing like he did canonically.
Miles still promises to help Peter, because Peter is on the verge of death and Miles is trustworthy and right now, his only possible ally. Normally he’d never trust such a dangerous task to a child, but… yannow
Kingpin sees the kid running, Aaron gets ordered to kill him. Since Miles doesn’t have spider powers to give him an edge, Aaron catches up to him, or Miles gets severely injured at some point in the chase for other reasons.
Definitely fatally.
canon event /J
Aaron tackles Miles, who’s already wounded and stressed, and realizes who he is and unmasks himself. Miles’s horror once Aaron unmasks, his impending death, and the fact that Miles used his dying words to tell Aaron that he still loved him and he could still escape villainy makes Aaron realize the whole great power great responsibility thing, and he decides to covertly double cross Kingpin to shut down the collider— and then apparently get these random ass spider people that just keep showering up home to help.