While the Doctor hadn't registered surprise when he'd opened the door to find the bear, he did show shock when the bear introduced itself. Hank? "Well. Ahhh, congratulations. I wasn't expecting that."
The alien eyed the bear for a moment, then stepped back to eye the entrance to his TARDIS. It would take some bending, but Hank might be able to fit. Might. "I hope you're a flexible bear. Can you get inside? I've..."
The rest was lost in mumbling and movement as the Doctor stepped further back to let Hank try and come in. He had other ideas for getting the large creature in, but they were complicated. The front door was simple.