"You passed out?" For a whole week. Okay, that was a little bit more than a tad alarming, but he understood the concept of practice and Nico seemed fine now, so he doubted it had very lasting effects. "Basically, it's a skill that you need to work at. That makes sense. Sounds like taking it to another planet would be dangerous though... considering what you just said."

As in, he definitely wouldn't be asking Nico about shadow traveling there, and he's hoping the kid has enough sense not to actually try it, despite his earlier words.