Vegeta is well aware he is part of that 'let the person go' group. And he still thinks Goku was an idiot for allowing him that. Yes, it worked out for the best, but it was a stupid move. A stupid move Vegeta was more than happy to had used to his advantage to get away, as much as that loss had been a major blow to his pride and ego.

"I'm well aware you're not." Trunks had proven that with Freeza, let alone his drive to take down the androids. No second chances, just finishing what needed to be done. "Good." Vegeta adds, then, after a pause, he also offers, "So will I." How annoying, however... he would. To keep this guy out of their way.