Sleep to escape

Paul doesn't know much about this world, but he has learned this. When he sleeps he is back to the real world.
Sleeping from exhaustion counts. And so far it has been his most common way of travel.
That kind of sleep doesn't allow him to recharge. He wakes up just as spent.
His favorite place to sleep is curled up in a corner behind a dumpster somewhere, trying not to spiral in despair. Which gets harder and harder the more exhausted he becomes.