I wanted to respond and elaborate about the secretness of the secret so I replayed the game and actually found the fourth ending so now I can actually state valid thoughts!
Yeah I mean, you are definitly right with your intentions and I can agree with it but also I'll describe this ending as such "A clueless enigma", since it's clueless there is no lead, so if you look for a lead in the first place you are already lost and that's what I did in my first play through ahah, the only (Clearly stated) clue I had was "There is another one!" to be fair there is another clue but you really have to be desperate and be trying anything, so I mean, that's it, I still enjoyed the ending just like how I enjoyed the whole game ahha and make of this comment what you want! No right answers just my description of it!