Sam supposed she hadn't actually expected the position to be open immediately. She'd known, when they'd talked about fixing his ship, that there might be an offer to fly off on it at some point in the future. She'd planned on figuring out how that was going to work whenever that happened; she hadn't expected it to be tonight.
"I think," she said after a moment's consideration, "That I'd probably like that. So long as it doesn't involve leaving my family behind-- I'm usually my sister's copilot, but she's not here at the moment. It's just me and my mom, though we're hoping she'll show up." She looked up at the Doctor. "So, unless you'd be alright with having all of us on board-- and I won't blame you if you don't, unless it's a situation where we really needed to be, if the Surprise dies or something-- I'd say I'll be your copilot unless they need me more. Or unless one of your near impossibilities shows up. And if either one of those things happen, then... we'll work it out when it happens. If that's okay with you."
Hopefully, that was a deal he could understand. Right now, it was very appealing to take the offer to work with him, because it gave her purpose and it actually felt like it might work. More than anything, she wanted something to work with and someone she could trust to work on it with her. If that was what he was offering, then she very much wanted to take it.
And it still didn't seem like it would involve flying off somewhere anytime soon, since they hadn't managed to fix the TARDIS. So she could still worry about that, and whether it would have to involve leaving her family behind, whenever they came to it.
"You must have a tub for a bubble bath in here somewhere, if you've managed to cope without a bouncy castle all this time," she said lightly, smiling. And his explanation of the library made more sense than what she'd been originally picturing, although it was difficult to tell whether he was actually true or not. The ship must have some limits, she thought, but apparently it was even bigger on the inside than she'd originally thought. "Did you just make a med bay by snapping your fingers?"
Having an infinite ship was obviously really handy. She wished they'd had a TARDIS (and a Time Lord, too) around at home.
She smiled. "I think we'll run faster if we're not holding hands," she pointed out, but she touched his arm briefly, just above his wrist, just to sort of return the gesture while still politely declining it. "I'm always ready to run. I'll follow you."