I just flicked through this at the store, but it looked like the Macguffin was laying on Wendy's legs, then Calculator smashed it on Babs, while Wendy was freaking out that her legs no longer work.
"Anti-Life Equation Doesn't Work Without A Price" or whatever... I'm thinking this is at the very least intended to be a way they COULD have Babs walk again. Whether or not they go in that direction, I'm not sure they've even decided yet.