Merlin smiled and shrugged, stepping aside so Arthur could get the door for him. It was that or try and take the keys back and do it himself, which would probably result in dropping everything else in his arms on Arthur instead. Papers, books, a couple groceries, and a couple other bags of random little things. He figured Arthur would rather just get the door.
"I do have a clip for them on my belt, but it's hard to unlock the door with them attached to my hip." He explained casually, glancing at the oddly wrapped box the blond held under his own arm. Merlin thought nothing of it though, something for Gwen he assumed. Once the door was open he wandered in, setting his bags and boxes on the counter, beginning to unpack.
"Coming in? Or where you going some where?" Merlin called, looking back for a minute. Arthur would have to come in, at least long enough to give his keys back, and Merlin would more then likely distract him by showing off the things he'd bought. The one he was the most proud of -- finally getting a much needed backpack.