To Steve the TARDIS just looks like a dressed-up phone booth, but he figures to each his own. It's clear to see that the Doctor thinks she's something pretty special, even if he can't get the door open.

"If she's a living creature," Steve asks with curiosity, "Why can't she open the door for you?"

Thinking on that for a moment, Steve eventually shrugs. "I guess I don't look at it that way. As a SEAL my job is to protect and to neutralize threats, preferably without combat. Not that combat doesn't happen but we generally shut it down as quickly as it starts up. Nobody likes the idea of war, but someone has to stop the terrorists."

With a tilt of his head, a smirk crosses Steve's face. "So you're saying you turn into a butterfly?" He might not have quite caught the correct implication of the metaphor used.