If you we're ever unfortunate enough to find yourself with marginal climb performance relative to the terrain in the missed approach area ( it'll probably do about 4% on one at 5 tonnes over MLW) , then the question you'll be asking yourself is " what is more important to me, clearing the hills/obstacles if we go around, or having the cabin pressurised while we are less than 10,000ft?" If you would rather clear the hills then simply turn the bleeds off.