It's been hidden over a year. There's a wall that barely does the job.
Yep, a tunnel would work too.
Ironically, as much as I hate the inclusion of kiddie character rides at Epcot, the Seas layover doesn't bother me because it was always the weakest theme. Although the hydrators were impressive in their time, the rest of the pavilion comprised 80s-style signs, a public television-quality film, and a tiny ride through a tunnel. TLS was never as timeless as Imagination or Horizons (new films would have fixed H). Nemo is certainly a better fit for Epcot than Poseidon or Mermaid would have been. Although I would have preferred no characters, if Seas had to have them, Nemo is okay.
But it needs a true exit to complete the suspension of disbelief.