This is the conversation between Peter Parker and Assistant vice chancellor in the Spiderman: No Way Home movie
Peter Parker: Yeah, I'm sorry. I really needed to talk to you and I know you're on your way to the airport. MJ Watson and Ned Leeds are the two smartest people I've met, and I'm the dumbest person because I let them help me, but if I didn't, millions would've died, so please don't let MIT be dumb like me.
Assistant vice chancellor: MIT is dumb?
Peter Parker: No, I'm saying don't let MIT be dumb. I mean, like the dumber version of me that wouldn't have let them help.
Assistant vice chancellor: You didn't rehearse that, did you, Peter?
The context is: Peter did let MJ and Ned help him. Because of that, millions didn't die. He's talking about a past event.
When I used AI, and asked why “If I didn't... “is used instead of “If I hadn't...”, it replied
This is because spoken English often relaxes grammar. Native speakers frequently use past simple where formal grammar expects past perfect, especially in fast, emotional speech. Examples: Formal: If I'd known, I'd have called you. Casual speech: If I knew, I'd have called you. Native speakers say this all the time.
IS THIS TRUE ??
It looks like wrong usage of mixed conditional !!