Add: I made a more detailed recount of the scene I saw while talking to someone on the original thread:

A young, short soldier (played by someone who I've seen play lots of soldiers - think a male Michelle Rodriguez) volunteers to climb out of an entrenched position while people are shooting at the whole group, and walk casually, without any cover, away from the enemy and towards a place where explosives have been clustered. He is holding a giant CB radio and has it set to the frequency of the explosives' trigger and just needs to get close enough for them to go off. Just speaking into the radio at that frequency will do it, so he's yelling and cursing at the explosives to go off. He keeps getting hit on his extremities, but he doesn't duck or cover, he just keeps slowly walking away from the firing. At the climax of the scene, he's bleeding and limping and just yelling "Blow!" Into the radio. A bullet goes right through his chest and he falls to his knees. He screams "Blow!" one last time and the explosives go off.

who I’ve seen in a few other movies typecast as a low-ranking soldier or officer of some kind

Can you remember any of the other movie titles? That'd narrow it down.