Toei’s official TV production webpage for episodes recently highlights and explains how the pivotal “underwater scenes” showcased in Kamen Rider Ex-Aid, episode 39 were filmed.
On July 16th, 2017, the 39th episode for Kamen Rider Ex-Aid called “Goodbye, Me!” aired, which gave main protagonist Emu Hojo/Kamen Rider Ex-Aid (portrayed by Hiroki Iijima) difficult decisions to make, which soon resulted in “underwater scenes” for both Parado/Kamen Rider Para-DX (portrayed by Shōma Kai) and the flashback child version of Emu himself (portrayed by Rai Takahashi).
Recently, Toei’s official TV episode production page released production notes for this episode, including how the aforementioned underwater scenes were filmed. The production notes are detailed below.
“The Ex-Aid team has filmed many scenes under rain or falling water, but this is the first time they’ve filmed something underwater.
This scene was actually filmed in a pool. The cameraman, Kurata, and Kai had to take staff training beforehand.
This has become quite an extraordinary experience for Kai. The same can be said for Rai Takahashi, who portrays a young Emu. The diving staff were present, to ensure the safety when bringing him above surface. The scene filmed young actor just barely making it in shallow water.
Although he (Takahashi) said the water levels were be okay, performing underwater is no easy task. Nonetheless, he was able to perform the task on the spot.
“The scene is a flashback that ties into the first episode” said Takahashi, drenched in water.””