First, some kids just need to let off some steam before they can get to sleep. Crying is perhaps his way of doing that. Some kids rock and bounce themselves, some kids bang on the wall with their arms or legs - and some kids cry. As long as he's going to sleep so quickly (5-10 minutes! That's nothing! half an hour is not a big deal.) As long as the noise isn't an issue for the baby, don't worry about it. It could be that by allowing him to let off that steam, you are giving him the chance to peacefully go to bed (peacefully after the crying.) I do agree that there could be some manipulation going on (believe me, he knows how uncomfortable it makes you when he's so upset.)
Second, is he still napping? He may be ready to give up the nap. If he gives up the nap, you may be able to leave the door open and he'll go to sleep anyway. It was about 3 when my son wanted the door open, too. It'll take him a little bit to adjust, but he'll learn to fall asleep with the door open. And while he's doing that, if he's quiet and resting, but still awake later, again, not such a big deal, I think. Give him a chance to figure it out for himself, and I think he'll find his way. Good luck!