The mirror wich is the portal to the hidden labroratory won't show up. I searched the Ruin under water for 1 hour now and I think the mirror just isn't there.

I think the place on the screens is where the mirror should be (at least I couldn't find one anywhere else either). The screenshots show my attempt to pass the mirror from the inside but I tried it from the outside of the ruin too. Shooting it won't help either and everything else is impossible under water


Am I just at the wrong place and need to get my eyes fixed or is this the place and the portal just isn't there?