It was entirely possible that she was bluffing about whatever he had in his hands. That she couldn't tell exactly what it was. But even if she could, she had no idea what was inside. River was smart, but she wasn't that smart. It was a bit too late, but the fact that he was trying to hide it from her made the corners of her mouth twitch up in amusement. Sometimes he was down right adorable. If they were anyone else, she would have reached over and ruffled his hair.
Instead of answering, she knocked on the door frame. "Better? Humans are precious like that. They always think they've invented everything. If I had knocked, you wouldn't have let me in." Not that she was in per se. She was still at the door frame, and didn't seem to be coming in just quite yet. Maybe she had some manners after all. Either that or she thought that she might explode if she stepped inside.
She hm'd a bit. "Honestly I've forgotten now that I'm mostly curious about what it is you're hiding from me. Getting ready to inject someone with something? What are you planning? I think that's the more apt question."