I agree... Is he crazy?!? I'd be eating, swimming, exercising, etc. while the opportunity presented itself!
If he were as smart as he says he is, he would be soaking up some sun and expending some energy because he's gearing up for a looonggg day in exile. Of course, something tells me that he'll have people sneaking in there every once in a while.
If it were I, I would probably go downstairs into the lions den...If I were alone in HOH with nothing to do I'd probably go mad.