The Doctor heard her enter and listened to what she asked but didn't offer a response right away. Staring at the thing before him, he turned his head to and fro trying to figure out what was ahead of him, and he clapped his hands together, rubbing them, "It's a thing. Well more of a thingamajig, but we'll call it a thing. It's a fun thing, I think, not really sure what it's going to do, but never had a thingamajig before. Everything I've had always had a name, a function, no real reason to just 'be' a thing."
He turned to face her and held his hands open, "But yes, you have to go out."
He moved towards her and placed both hands on her face, squishing her cheeks together a bit, before kissing her forehead and moving past her into the main hallway, "Alright, fine. Yes I suppose you can go--but first, why?"
Pointing at her, "You're excited. I've never seen you excited before. Your heart rate's up a bit, your pupils are a bit larger, breath's a bit harder to catch. What's got you so worked up--"
Then, he frowned, "And how am I supposed to be certain you'll be coming back?"