Ight, so what about the fact that he was somehow surprised the baby was already born despite hearing the baby in the background during the phone call?
That's the part that actually made me say he's slow
I never said he wasn't being stupid! I said that I
liked that he was being stupid here. His thoughts are stupid and there's no reason for him to be thinking any of them. If he slowed down for a second, he'd be able to go "... wait she's
obviously not pregnant, what am I thinking? She probably has to babysit or something." But he doesn't slow down, partially cause he's a dumb kid but also because, I think, he starts to become invested in this story he's telling himself. He's gonna have to marry her and it doesn't matter who made her pregnant, because it's
her child. And he's going to love that child as much as he loves her, and he's gonna step up and be a father for- oh wait she's literally babysitting. Never mind, then. Never mind. Forget I said anything.
I also don't think he heard a baby. There's nothing to indicate that in any of the dialogue. He hears 'baby' and immediately starts drawing up his soap opera leading man arc. He says he'll be right over, takes off, and broods on the train about how he's going to be a father for this child even though it can't be his.
See it's honestly really fuckin' funny and that's why I like it. It's a comedic overdramatic misunderstanding where a character gets pumped up to do a really serious and mature thing but it turns out it was just their imagination.