My girl has a STRONG feed drive (she will grab off the tongs, often reaching out of the enclosure to get it) but only when the smell of rat is in the air - I wouldn't dare put my hand in there when a rat is in the room! I'm also very careful not to touch her rats with my hands; I don't want my smell mixed in there.
But between feedings she is friendly, shows no sign of aggression and will occasionally crawl onto my hand in the enclosure.
Extrapolating from my piggy, I'd presume that feeding in another enclosure puts you at some risk of being bitten if the smell of food is still in the air and they mistake your hand for a second meal when you reach in to move them back?