JMcAndrew ponders:
Does the military train soldiers with live grenades? How did they survive this? I’m starting to think that this comic isn’t very well thought out.
Which of course brings to mind the Holy Hand Grenade of Antioch:
I’m betting I’m not the only one among us who has irritated their spouse by counting “One, two, five!” on occasion.
Comics I Don't Understand 
I certainly hope that wasn’t a live grenade. Sarge is freaking out imagining what would have happened if it was.
Yeah, the Army trains with live grenades. Mostly they use practice grenades which are heavy fireworks but they use live ones for qualification tests and some of the training. Zero should have qualified in basic though.
Throwing the pin is an old joke that gets made by approximately every soldier at some point.
If we assume it’s live and you need a realistic explanation for their survival then you can imagine that Zero then throws the grenade. Four seconds is plenty of time (IIRC it was longer with the old pineapples they’re using for some reason). They’re recognizably at a grenade range – that wall behind them is topped by grass at ground level. It doesn’t have to go very far for safety.
That’s assuming Zero even released the handle – which is what starts the fuse. We don’t see it in the second panel, but we also don’t see an indication that Zero released his grip. Despite the poor drawing, a grenade handle goes all the way down.
We trained with “practice grenades” in basic training. They were hollow spheres with only the primer cap. They made a cool “pop” noise. After a lot of practice, however, we did a “live fire” exercise with two real grenades.
The trainee is in the foxhole with a drill sergeant. He pulls the pin and tosses it over the wall. Before he can even bring his hand back, the drill sergeant is pushing him back down in the hole. My first throw was short. The drill sergeant asked if I even wanted to throw the second. I did not, but I knew I’d never live it down with the rest of the platoon if I didn’t. So I did.
Nothing truly prepares you for holding something that can blast to hell. It’s scary as all get out.
Fun fact: In the original script for “Monty Python and the Holy Grail,” Arthur named five knights that had fallen to the rabbit. Two of the names were then crossed out, and the line “Three, sire!” written to the side.
Some years ago there was a published script that had all the written, but not filmed bits in there but just marked out with grease pencil. There were a number of cut scenes.
“Stop! Who would cross the Sea of Fate, must answer me these questions twenty-eight!’