"Simple. I only need a quick boost to keep me going for maybe another half-hour, so you probably won't even fall asleep from the energy loss. If you do fall asleep, then that's no problem for two reasons. Firstly, I would simply put energy back into you until you woke up. It's a two-way process, so don't worry about that. Secondly, while you're asleep, you gain energy from recent meals and other stuff, which is why you sleep when you're tired and wake up feeling refreshed, so you would in fact be gaining energy whilst asleep rather than losing it," he explains, another rumble erupting from his gut.