[Pepper's smile imperfectly masks lingering unease. Still, she answers him.]

Because... I was the first person it was tried on, so it was unknown if it would work until I came out of it again. As for now, it seems like the ship only has so much power. Using it to cure too many people might put the lives of those still in stasis at risk. That, and there's no guarantee if it would work on someone who didn't come from the ship.

Long story short, it's better to use medicine.