Tom had his back against the door so he understandably didn’t see his guest come in. Still, Henrik was shocked that Tom hadn’t sensed him. Tom wasn’t one to be so inattentive. He had to be really distracted, which he was. All his attention was on the photo he held in his hands, one of Henrik and him together on their first ever Hogsmeade trip. Abraxas had taken it for them after much convincing on Henrik’s part (and threatening on Tom’s).