Monte hates being separated from Carlo, and he quickly works himself into a desperate and distraught frenzy trying to get back to him.
This morning, Monte slipped into the bathroom without me noticing just as I was leaving, and I accidentally ended up locking him in. I got back at lunch and did not notice anything very amiss, except for the fact that while Carlo trotted up to greet me as usual, Monte did not. Then the scratching/tearing sounds coming from the bathroom. I think that given another a hour or so he would have made it all the way through.