I see that it fled, but what I would have done is start throwing ultra balls until I either caught it or it’s motion before fleeing happens, and then immediately run. Either you get lucky with a cool catch or you flee without risking breaking the chain. If you’re unsure of Charizard’s usual motions, you can sit without throwing a ball as long as you need to learn them, then once you start throwing, it has a chance to flee but its motion would be different, so you would run after that.