It took a certain degree of finesse to become someone the Doctor deemed endearing. While everyone he'd spoken to thus far had managed to worm their way into his hearts almost instantly, if only for their intelligence alone, he had a particular interest in Sam. Maybe it was due to the valiant nature she possessed that rather reminded him of Rose. The Doctor couldn't say--wouldn't, he just accepted the sentiment with a delighted smile and moved along.
Because he could--move, that is. He could talk, ramble, pause to collect his flabbergasted thoughts, then question the air once more. He was doing precisely that when Sam arrived. The doors of his TARDIS were flung open, several tubes and wires still occupying the entryway and bleeding into the halls, but he'd done some tidying since Cristina had (understandably) grumbled at him for the mess so that it wasn't quite as horrific at first glance.
Before the doors and balancing precariously on an over sized tube that looked hardly stable, the Doctor's back was to Sam as she let herself in. His hands rested on his hips, brown overcoat thrown over a nearby chair which was covered in various tools and a console panel, and his hair looked like he'd been clawing his hands through it pensively. He had been.
Hearing his name, he turned without losing his balance and his smile lit up at the sight of Sam. She had come to satisfy her curiosity after all. "Hello there, Sam!"
Hopping off the tubing, the Doctor kicked it aside to clear a better path for Sam. All but hopping to the threshold of the TARDIS herself, he spun around and extended his arms inside in a welcoming gesture. "Excuse the mess, have a look! She's seen better days, but she's not sparking anymore. Lights all in order and the bizarre smell of--well, not important--it's gone. I promise there's more than enough room for two in here."
He grinned, giddy as ever just to show someone new his beloved ship. Having the chance to do so again had all but supplanted the despair he held toward dying. The Doctor did try to make good on second chances, even if they didn't always work out with every person fully satisfied.
He shuffled a step inside before her, fingers nudging his glasses up the bridge of his nose as he eagerly awaited whatever reaction Sam would have to the interior. "Welcome to my TARDIS!"