Good. Just stay with me, Carlisle... you can do that, can you not? Just count the seconds if you have to. Or, I know—try to think of all the nice things we will do together once we have fixed this once and for all. What is one of the first things you would like to do with me once your body and energies have been truly restored?

This might seem like an overly-fanciful way of thinking that's leaping too far into the future too quickly, but its purpose is to keep Carlisle awake and with him as much as it is to inspire hope. Getting the cleric to think and focus will hopefully keep him from drifting off while he makes the last legs of his journey... and the ice alien knows his voice has managed to ground his partner in the past. Hopefully all of these factors can work together to help Carlisle endure, even when it seems like so many things are conspiring against them.