Pretty good chapter. I don't like that Sanji's still allowing himself to be swooning when such his crew is in peril. But I guess we just have to deal with it. Brook and Pedro going on the offensive is pretty sweet, even though locking them out of the room seems bizarre that they'd be incompetent enough to let that happen. I also like the elaboration on the nature of the Barbarian Chess Army, and that Brook finally has a latent advantage over something.
I'd wager Purin is going defect or rebel, as we see she had a solid relationship with Lola, and she holds the Straw Hats in a high regard. She says she's going to screw things up, and the easiest way for her would be to anger Big Mom. If she does that by running away, then that would be... bad. For everyone. She could either do that or refuses to marry Sanji, which the only difference there is that she's still in the line of fire.
She may end up being responsible for liberating the Straw Hats, but I feel like that would be after everything's gone to hell. I think if she can get Sanji's bomb cuffs off, then they could escape, but then they would have to focus on their own survival. It's also just as possible that that's phase three in Brook and Pedro's Excellent (Mis)Adventure. I think it would be easier for them to save Chopper and Carrot, and then use their relatively full strength in a jailbreak.
I keep having to bring this up in whatever thread I'm browsing, but once again, having Law here solve a lot of problems like moving the Poneglyphs, infiltration, jailbreaking Luffy and Nami, making sure the chef can still cook when this is all said and done, taking out the major threats, prescribing medicine, moving furniture, removing splinters, trimming the cat's nails, helping with homework, cleaning your room, taking out the garbage, folding laundry ... the list of things Law is useful for goes on and on. Really, every house should have one.