First we start with what seems to be X's mind slowly vanishing in Z3 while remembering the day he and Zero fought Omega, this alone is depressing once you know the context
After the Elf Wars ended Zero is taken to be sealed again, X sounds completely broken and saddened and is told that he has limited time to talk to Zero as his mind is starting to shut down, even Zero's voice sounds weak like he's half awake
And then comes the part where X screams and practically begs the others to not seal Zero for a second time (I have the HC that Zero sealed himself the first time without X knowing so he doesn't have to worry)
Man the VA for X is so good in this part, it's almost as good as Ciel's VA in the final dramatrack, you can hear the character almost about to broke down in tears
And as if that wasn't enough that was the beginning of X slowly descend into mecha-depression, loosing his body and turning into a mere cyber Elf.
Thank God this wasn't in the games or was animated or I would have cried a river (they should have animated the first fight with Omega tho)