I cried. I cried a lot. I knew one of them was going to die and I braced myself. But the events that unfolded were too much. No one was at fault, both boys were justified in being panicked and being scared into firing like that is 100% logical. And in the end, 3 kids who were the beacon of hope for humanity died for no reason. Had it happened through malicious means or a normal accident like a stray bullet, I would've been sad but not sobbing like I was.
The way my uncle died was also way to random, I really didn't like it
P.S: My uncle didn't actually die, I just wrote this as a very roundabout way to reply.
I guess thats the point the author tried to make. All the build up can be rendered pointless in face of randomness. Life is not cruel by showing you what is emotional and unbelievable. Life is just indifferent.