Well, Atlas did say that plasmids were what messed up all these people, but he also didn't sound too worried about Jack taking that one, so... Atlas'd tell him if there was a problem, he thinks. I mean Jack is helping him rescue his family, they're tight.

Also those sure were some words. Jack may possibly definitely be looking confused. Explain like he's three, please.

"I don't feel different." That one's less defensive, more just stating facts.