When Lalo stands up to get extra air,the crack sound is that of Baku breaking the regulator.He probably used the metal card to break it hence the thickness bubble on the last panel of pg 3, ch 431.The supposed theory is that Baku broke the regulator so that he can get the meter to zero whenever he wants.So,he can change the bios before it runs out.Thus when baku loses a round at some point,Lalo will think that he is in the safe zone even though he's not since the already used bios still have some air in them.Thus he will fold the rest of the rounds and give up the ante which lets baku win.
But,in the last panel of pg 17,ch 431, lalo seems to have seen the broken piece.So,the real play seems to be that baku only broke the glass window and not the regulator itself.Thus Lalo will be tricked into playing even when he reaches the safe zone which provides baku immunity atleast until the end of the last round.
edit:it also gives baku time to figure out the law.