Other mistake: When Max's wife goes to get ice cream, you can see Max's black Interceptor in the driveway of one of the house, right before one of the bikers loses his hand.
Other mistake: When Jessie realises that her baby is missing, she runs out into the yard, stops and does a slow 360 turn before looking forward again. She then hears the Toecutter's voice, looks to her right and sees all the knightriders, including one holding her baby. So somehow in that slow 360 turn she did previously, she somehow managed not to see 15 knightriders standing close to her.
Other mistake: At the end of the opening chase, there is a sudden flaming rocket-like burst from the back of Nightrider's car. Other shots of the rear showed no nozzles for this.
Answer: He kills the members of the gang directly involved in the attack on his wife/child, and the one who ordered it.