[Speculation] Theory about Luke

I know it's not a hugely popular opinion, but I think Luke's done something terrible between RotJ and TFA. Now, is it something so terrible that he's gone full dark side/Sith light? Doubt it. Too big of a bite for people to digest. But something smaller scale or, more intriguing, unintentional? I think that's on the table.

I have absolutely no proof of this, but I swear I remember hearing a rumor during filming of TLJ that they blew up a building with Mark Hamill on set. Could be anything, of course, but if you pair it with the theory that the (presumed) academy destruction scene from the teaser actually has nothing to do with the Phasma blowing shit up clip that comes right after, you start to get the beginnings of an idea.

The idea being that Luke has some significant role in the destruction of his academy. Did Kylo's fall enrage Luke so badly that he blew up a building full of his students on accident? Did Snoke and/or Kylo and the Knights of Ren start turning Luke's students making Luke choose between more Snoke followers and slaughtering dozens? Who knows. Insert your own trigger here.

Either way, it comes down to believing that Luke has it in him to commit some act of evil if pushed too far. And I think we already have ample proof of that from RotJ. When Vader, who Luke had previously committed to saving, threatened Leia, all bets were off. Vader would've been dead if Palpatine hadn't been there cackling in the background reminding Luke of the consequences of taking that last step.

Take away that potent reminder, add some grief, embarrassment (?), feeling of failure and/or betrayal, and you've got a cocktail of rage waiting to be released. How it manifests? Well, the only thing we have for sure is that the last time we saw Luke get pissed, he came a razor's edge away from turning. My guess is that Luke's hiding from something dark that he did in the years between Endor and TFA.