He'd told Thor it was fine not to knock if he was expected, but it was oddly charming that he knocked anyway. It was rare that Thor was so meticulous about things. Loki had expected his brother's drunken promise to hold for a week, at the very longest, but here it still went on. He considered actually getting up to answer the door, but he was sitting on the floor surrounded by books, paper, and pencils, and it seemed like too much work. Instead, a little telekinesis cracked the door open and he called, "Come in!"