Leo manages not to sigh when Don vanishes after Mike and Raph, leaving him alone in the kitchen. He's pretty sure Raph had left so discretely to avoid the whole house trampling after him, but there's no stopping Mediczilla when he senses someone trying to escape from his care. His mind goes back to the yellow-tinted concoction in his brother's hands.

... couldn't hurt to try.

Getting to his feet, Leo unsteadily makes it to the threshold of the kitchen, eyes tracking Don's shell. They stay there as he climbs onto the sofa near the bathroom, giving a low groan that breaks off into a few coughs. He'll just keep tabs on them from here for a while to make sure Raph isn't dying.... and then maybe make his own break for it.