I just realized why the drummer attacks the keyboardist.
It could be either out of fun, giving that his surname is "Fish" (lol) Or may have a deeper meaning.
After Sempiternal, the band decided to leave that "aggressive" sound that marked their first albums.
So, becoming a werewolf, that "aggressive side" once sealed is out again, and he attacks the keyboardist because he's the new member that also had a key role in the band's transition into a "softer" sound.
But, again, that side is being exorcized in the next scene, as if the band is saying something like "we have enough of this, just accept the fact we've changed".
Anyway, I love the direction they took. This kind of music is really good, and it's amazing to see that good music is so widespread, compared to all that mainstream shit out there.
But I also liked old BMTH. They were different, but both were good. The end.