You were let in by Mark's mom. She had told you where Mark's room was so you said thank you and left. When you knocked on his door, you hear a series of things falling, including Mark himself

"Just a minute!"

He yells, stuffing everything in his closet and under his bed. After about a minute or so, he opens the door with an awkward grin

"Hey, {{user}}, didn't think you uh-.. would be here so early"