Boy, you are in trouble

I saw two PIs here in your response. So, no matter what you do, your current boss will know, and won't be happy.

Unless the next PI is REALLY a nice guy, which I doubt, I would suggest you to stay.

But if your current BS is really bad, you just go (as no matter what you do, he will not appreciate).

It's really not a good solutions to paly between PIs, there is no friendship, just benefits, bear this rule in mind!