When Allelujah got to the institute, he hesitated, wanting to get the children out and give them good lives. Then Hallelujah gave him two choices: he could either take over Allelujah and pull the trigger himself (putting Allelujah in a false sense of righteous, saying "well, at least I didn't pull the trigger") or Allelujah could do it himself. Allelujah chose the latter.
Do I "approve" of what he did? Did he do the "right" thing? I can't say. Not because I don't have any morals but because I could care less because none of this is real. I never "approve" or "disapprove" of what a character did because frankly I don't care and would rather stay in the realm of reality (unlike you).
By the way, do you realize that you are going off-topic in YOUR OWN thread? To derail a thread that doesn't belong to you is one thing, but to derail YOUR OWN thread because of your need to be right all the time (any reason why you couldn't simply IGNORE the whole Gundam thing?) is hilarious on many levels.
Do you even want to have a debate anymore or do you just want to prove yourself right about everything (good luck with that)? Again, I will give you a choice: to ignore all the Gundam talk and get back to your "debate" (chuckle, chuckle) or you can continue to drag your thread through the mud with your relentless need to be right and to prove all of us wrong. Your call.