How can I detect if a Player is under a certain brick?

In this project im workin on, it's possible for players to walk on water if they have a certain skill active. I just use a local script to set a transparent part put over the water to cancollide, and since its in FE, the local script only makes it can collide for that one player. https://gyazo.com/154b37f02bac3b143e2829036705752d

But the problem with it is that if the player uses the skill underwater, they get trapped under the part until they cancel the skill. Anyway to detect if they are actually under the part so that I can stop this from happening?

thanks for reading