Nothing. Nothing is keeping him from fleeing forever. Let him run, but now you have a gun off the streets from the car he abandoned. Nobody got hurt and you got to impound a car and add a charge for whenever you do get him.

Even with the added crimes from the stuff found in the car, all of his new charges had zero real physical victims, all just "rules" he broke. So yeah he should answer to those rules he broke, but up to this point the zero some of the victims on the current charges is zero, why not work to keep it that way?

The dude just wanted to run away, let him run away, he was out of the car and you lost control. He won the day but will still end up in jail at some point. I am not advocating for cops to never apprehend someone, just that once you have lost control and the "bad guy" is de-escalating you let the de-escalation happen. This keeps both the "bad guys", but more importantly the police safe as well.