How did this episode come about?

While we were shooting Season 1 last year, Wade Allen, our stunt coordinator, told me: “Hey, if you ever need a little girl to do stunts, I know this girl Jessie. Her parents are both stunt people, and she’s amazing. I just worked with her on a commercial, and she can do fights, and she’s a gymnast.” I was like, “That’s cool.” It stuck in my head, and I have a little notebook that I write things down in. I wrote out that idea — Barry fighting a little girl, and her running up a tree on top of a house. I just had these little images.

Did you decide to direct the episode because of your vision for it?

Yeah, I saw it very clearly, and I wrote it super specifically. It was very strange because usually, when we write episodes, it’s [the show’s other creator, Alec Berg], me and the writers in a room. But this is one where I came in and pitched it to all of them, and they were like, “That sounds crazy!” It was a weird thing I was cooking up privately that I told them about, and they were into it.

How did you find Daniel Bernhardt?

It was hard because in the script, Ronny was a short, fat, bald guy. He was this schlub, and it was this weird reveal that he was a taekwondo master. That proved incredibly hard to find. Most guys who are skilled like this are really good-looking like Daniel. He came in, and all the women in our casting office were like, “Can we please cast him?”

What was it like working with Jessie Giacomazzi?

She’s brilliant — so sweet and a really amazing actress. Her character thinks her father has been killed, and I didn’t want to lose sight of that. I said: “This is a very primal thing that you defend yourself and seek some sort of vengeance. Think of yourself as an animal.” We kept going between squirrel and tiger. She really understood the character.