Back in Tuco's abuelita's garage, Zuke tries to pin the whole thing on Saul WHILE HE'S CUTTING THEM LOOSE, and just like that, we're out in the oh-so-familiar desert, everyone is tied up, and Tuco sends Nacho to the truck to grab the "nuclear option" (in this case, wire cutters).
The desert is where the Jessie Spano caffeine pills thing comes in. Saul talks his way out of having his fingers wire-cut-off, and instead of hopping back in the van, fully fingered, Saul puts himself back in harm's way -- something he avoids at all costs in Breaking Bad -- for the same two dudes who just sold him out. "You're tough, but you're fair. You're all about justice," he tells Tuco, but really, he tells himself. Saul is fighting becoming Saul, he's trying to do what's right, trying to be more public defender and less Slippin' Jimmy. And that's where Jessie Spano and Saul Goodman diverge -- Jessie's self destructiveness acts as a means to maintain her public perception, whereas Saul's self destructiveness acts as a means to build the one he thinks everyone wants him to have. He somehow bargains Tuco down from skinning them alive to breaking just one of their legs each.