Just rewatched it. Pretty sure the first driver is the decision to banish Kevin up to the attic alone, rather than with Fuller (same scene as he says “I wish you were all dead”). It could be the going to Paris, but the story wouldn’t happen as it does if Fuller were with him (as initially intended), which leads me to think it’s that solitary banishment that kicks everything off.
Here’s where I think the drivers lie:
- Kate banishes Kevin to the attic alone.
- The Bandits select Kevin’s house as ‘the one’.
- Gus Polinski decides to offer Kate a ride.
- The Bandits decide to hit Kevin’s house, regardless.
- Kevin decides not to tell anyone what happened.