Fifteen people are in a locked, windowless room.
#1 thru #10 are just random people.
#11 thru #15 are siblings.
#11 has a gun. He's waving it around and saying all kinds of crazy things. He has a long criminal record. He beats his wife. He's a major-league sociopath.
His siblings, #12 thru #15 are embarrassed and alarmed by his shenanigans, but #11 won't listen to reason. #11 is sensitive about his mother, and he makes this clear to everybody in the room.
"Anybody jokes about my mother, I kill him."
His siblings, while they might also be offended if someone insulted their mother, are at least reasonable about it. They don't like guns, and they are relatively sane.
So #1 thru #10 keep their mouths shut. Perhaps in the future they can reason with him, or disarm him, but right now, he's bat-shit crazy, and waving a gun.
Everybody keeps quiet except #3. He says:
"Your mama's so fat... "
BLAM BLAM BLAM
The crazy guy shoots #3 dead, as promised.
Now we all agree #11 has to be stopped, somehow. We understand the sibling's embarrassment about their psycho brother.
But what about #3?