ANDREW: We needed someone who would sort of bite back.

ROB: In fact in this interrogation scene she walked in like she owned the room. This was the audition scene.

ANDREW: Yeah, this is the audition scene. It’s a taugh scene because we are trying to establish both characters, we are also trying to establish elements as antagonism and sparks here. She thinks she’s interrogating him, and he thinks he is on his first date.

ROB: Yeah, this was kind of our mantra. We went through the process and there was just nobody else who that moxie that she had –

ANDREW: And also the chemistry, you know, in a show like this it’s the chemistry of the leads that’s gonna be the engine of the show.

ROB: I’m getting you this, it’s that you…you sort of kick the right, you know, the first person, you got Nathan, you find Stana, and now you hope that…you know… after countless people, you know…Nathan was always our first choice, but we had to look other guys, and we ended up choosing Nathan anyways. Then you put them together and say “Do these two people who would’ve never met have serious magic chemistry that will last for years?”And you don’t know that. So you just put them in a room, and you start working. And…once we realized we had it, then the rest of the show you felt like “Well we have the most important thing which is the chemistry between he and her now, let’s build the show around it”.

STANA: Didn’t you guys have to pull back on some of the chemistry for the first episode?

ANDREW: Yeah, there was a little bit of concern that you guys looked like you were gonna go to bed in the second episode.

(Andrew Marlowe, Rob Bowman, Nathan Fillion, Stana Katic, Jon Huertas episode commentary)