@Taco was the cure said:

That broke my heart. The daughter.

Why did they put that part in the story at all... I would have liked some hint that he was gonna start have her in his life again. The way she came with the money for him, it's so realistic. Everyone who lost touch with their fathers know that.

Yes, that is a sad scene. I'd hoped that there would have been a post-credit scene, where the FBI arrested the corrupt cops working for Serrano, including the ex-wife's husband Captain Ted, who was probably abusing Walsh's daughter, Denise.

. "Midnight Run (1988)" - Scene with his daughter

I don't think it was necessarily as bad as the cop abusing the daughter. I think the film was trying to be more realistic and making the new husband out to be corrupt but not evil. But just the separation of daughter and father alone and the feelings she had for him after her early childhood was some sad shit.