"No. It's not that easy. I'm not going to bore you with the science of it." The Doctor sighed and studied another sample through the microscope for several seconds before pulling away and rubbing the back of his head. "Tell me, how many people are looking for you in your own century? I mean, I can use the TARDIS to just break in and out of a hospital... I should probably do that anyway, I really don't want to risk this thing spreading."

As he thought out loud he walked closer to John, noticing how sleepy he appeared. Damn it, this was not good, not good at all. "Er. What keeps you awake? We can't risk caffeine... I don't know, sexual fantasies? Anything, come on."