Hmmm, well, at least I don't have to wonder any longer. I found him.
He did get out after all. Pretty gruesome.
This is what he managed to get out of:
He either got out through the little uncovered gap by the locline or the right hand side because the acrylic was starting to warp and lift a little on that side. I've been wondering all week how to fix that warp but .. well I guess I don't need to worry about it anymore.
Guess if I every try again I'll have a huge box built around the tank top so that there is ZERO chance of escape. I won't put any eels into my 280g now because as an inwall tank I don't know how to enclose the tank 100% AND still be able to feed the fish on a daily basis (and not make it a huge burden for anyone taking care of the tank when I'm away on vacations or work or whatever).
I feel so ... unbelievably affected right now.
Part of me wants to feel sad about the eel (and does), part of me is like ... I should be relieved it's not something worse, .. and I feel for my friends at the restaurant. They are going to be so traumatized.. I .. feel so incredibly heavy hearted today.