First off, welcome to Dakka!
Next... on to the story...
I liked the rather hopeless aspect of it, it was reminiscent of WWI trench warfare where you'd spend thousands of lives to get across No Man's Land simply to have to move back to your own trench lines. Purposeless gains, and all that.
As it moved along, you did a good job depicting the strain that Antonius was felt, though I think you may have emphasized a little too much how tightly he was holding his lasgun.
I don't know why, but my favorite part was probably the portion where he kept shooting, hiding, reloading, etc. It rang rather true, as oftentimes in a combat environment you get focused on the familiar processes that you know and can control.
And now for the nitpicky git in me to come out for some constructive criticism:
“Ten minutes until expected the expected traitor forces arrive! Take cover!"
Check out the underlined portion and you'll catch the error
The pacing seems off. For references, it starts out at 10 minutes, then they're less than a mile (it may be worthwhile to note that
IG use the metric system, I catch this in my own writing quite often), and abruptly they're 100
ft away. Less than a mile sounds like, to me, almost a mile, which is 10 minutes at a standard jog, and it seemed like a very quick transition from ~5000
ft to 100
ft (as I said, nitpicky crap haha). I'd say "they're only a few hundred meters away" or something along those lines to give more of a sense of urgency to that portion rather than the comfort of almost a mile in a wooded area.
The forest they were in was the perfect place to stage a decisive battle for the traitors
This portion was worded a bit oddly, it's grammatically correct but for some reason it seemed to me to confuse the issue as to who had the tactical advantage until the next sentence. Could just be that I'm sick, congested, and can't really think too well, but it's something to consider.
Last thing, I like the futility of the ending, though something to make his plea to the Emperor more dramatic would be to have him actually state it, or whisper it while coughing up blood, or something like that.
All in all, a good little story. Again, welcome to Dakka!