I went through it, released the guy at the end and nothing more happened, didn't find any further paths, and returned to the beach. However, I played it one more time now and went around the abandoned building a bit more after recruiting Boyle too. There's doors you go through without a path back, or going forward and backwards taking you to different rooms. I presume it's an intentional shifting dungeon kind of place? Since there's no reactions from characters or mysterious SFX when it happens, I honestly can't tell if something intentional or not happened. I also sent all my team to 1HP with the vending machine (I thought I was dealing it damage and thought I had to mash to destroy it. Again, no reaction from the character and the screen flashed blue, so it didn't respond like damage.)
My exploration was then cut short because trying to jump from the top support thing towards the top of the waterfall has Abe jump down towards the middle waterfall. The only direction I haven't gone to is over there, but I can't reach it. Also, there are two different padlock exits that lead to the same place. After exiting through the first one once, I expected the second one would lead to a different place...

Also, down here there are some many sentry camera enemy icons, but defeating one of them deletes them all. Bug or feature?