“There were no bathrooms in the tunnel,” Patrick John Flueger recalls.
Warning: This article contains spoilers for the Feb. 22 episode ofChicago P.D.
First, a car backfiring caused a panic attack at home.

Marina Squerciati as Kim Burgess and Tireni Oyenusi as Jamie Bagley on ‘Chicago P.D.'.Lori Allen/NBC
The big episode was one that Squerciati didn’t have a ton of time to prepare for.
“Without the words, you’re able to’t really track the journey.”
“It was insane.”

Patrick John Flueger as Adam Ruzek on ‘Chicago P.D.'.Lori Allen/NBC
One of the guest stars, no joke, used a coffee cup."
The difficult scenes didn’t end there for Squerciati, who spent some of the episode in a well.
“I was in a pool for 12 hours,” she says.
So there’s no way to get me to the top to shoot me dry.
So I only got one take of that."
Thankfully, 200 episodes in, one take was all she needed.