To understand what happened, think about it this way:

Imagine if you realized a giant conspiracy to kill and/or torture you -- one even including your close family members -- but knew nobody would believe you. Imagine watching it unfold in front of your eyes, and you feel helpless, as you are 100% sure it's happening, yet there's nobody who is willing to believe you or do anything to stop it. Imagine believing that anything done to you will be blamed on your supposed mental illness, and that gives the enemies carte blanche to harm you however they wish.

So you're in an apartment, and you know that guys are there and will take you away to torture you, and your "going missing" will be blamed on your mental illness. Finally you just decide you'd rather die than let them get you, so you jump off the balcony to end it all.

That seems to be what happened here. To the rest of us, this line of thinking is absurd, and can be reasoned out to be paranoia. To Matt it was real, and he felt that nobody was aware of what was happening, and he had no way to convince anyone else.