It took several weeks for production to create the flooded basement set, which they constructed inside of a water tank. The Tank was designed so the special effects team could control the water levels, and keep it filtered and circulated so the actors and crew members were safe.
The Reapers' hwacha is a kind of rocket launcher that was first developed in fifteenth-century Korea. The earliest hwacha was primarily used as a defensive weapon and could fire up to 100 arrows at once.
At the end of the episode, tribute is paid to Stephen Campbell. He was the director of photography for 36 episodes of The Walking Dead, along with S10's original finale "A Certain Doom", and passed away in November 2021.
Executive Producer Greg Nicotero was so excited for the underwater walker kill that he practiced the stunt in his own swimming pool. The water even turned red for three days due to all the fake blood that he pumped into his pool for the test run.
Seth Gilliam remembers that Dikran Tulaine, who plays the Reaper priest, had an interesting idea for their scene together. "We did one take where I come into the room, and he rushed to embrace me. I had to tell him you can't hug your enemy in the apocalypse."