Revealing mistake: In the sidewalk scene, after one of the robbers leaves the bank and dives into the car, and it drives towards Harry, you can see a wire rope that appears to have been used to either stop the car from going too far or has been used to help roll the car. (00:02:07)
Revealing mistake: Near the end the psycho killer pays a black man to beat him up so that he can then blame the injuries on Dirty Harry. Watch the killer's hairdo as he gets punched and beaten: a couple of rear-view scenes show an obviously fake wig, intended to look like the killer's own bad-hair-day style. (01:16:05)
Revealing mistake: When Harry kills Scorpio with the last bullet the deadly wounded Scorpio looks back over his shoulder while he is flying into the lake to prepare for the dive. (01:36:15)
Revealing mistake: When Harry is drinking his cup of coffee with Lt. Bressler at the police station, look at the cup Harry is drinking from and you can see that is empty.
Revealing mistake: When Scorpio robs the liquor store, the bottle that he was going to purchase is used to hit the clerk over the head, but you can see it is empty.
Revealing mistake: When Scorpio slaps the boy in the school bus, you can see that Scorpio's hand actually misses the boy's face.
Answer: If you watch closely, you see the killer throw him to the side and then take aim at Harry, at which point Harry shoots him. Since we don't see the kid again, we can assume he ran away as soon as the killer let him go.
Not true. Actually, Harry sees the boy, and appears to be lowering his weapon, and then blasts Scorpio... and when the bullet hits him, he is still holding the boy hostage... It is only after Harry shoots him, and he falls to the ground, that we see the boy running away.