Innate Nature

The major wasted no time and fumbled in his uniform for a gas mask. 

Mark meanwhile, knowing that he didn't have anything of the sort, instantly dropped to the ground and began searching the dead soldiers for any semblance of something that could fully cover his face. 

Whatever side the bodies were on held little importance to him except for the fact that the likelihood of having a mask would be higher. After all, they would essentially be sacrificing themselves if they didn't come with at the very least a means of protection against the weapon they were using. 

Sadly, It indeed seemed that there was not a single semblance of a gas mask on their bodies. Their tunneling might have actually been a suicidal rush. From utter stealth to the sudden explosion, the events might have simply been a cover for the gas to disseminate across the trench before the other side realized. 

"Shit!" 

Looking over, Mark saw that the major, Paul, was also unable to find a mask of his own. 

The two looked back up in utter dread as the wall of gas approaching them began to break and descend. 

They dashed into the tunnel which was miraculously not blown to pieces by the explosion. Maybe the detonation somehow happened outside of the tunnel. Though they were not expecting to avoid the gas altogether there might at least be a mask in there. Holding onto this hope, the two ran without the slightest glance back, knowing that they might just see a deathly white cloud of gas rushing forth. 

Losing sources of light, they scavenged each and every corpse they could get their hands on, quickly patting the body down before throwing it aside and moving on. Time was burning away and they needed to act faster than death was approaching them. A thorough inspection was not in their cards. 

With his frantic hunt for a gas mask, Mark quietly, peacefully thought to himself in almost silent, unmemorable words. 

'They chose to use gas this time... not a bad idea at all. Since the soldiers were all preoccupied and focused on the explosion, they weren't able to see the steadily advancing nearly cloud-like substance in the sky.'

Perhaps the only two flaws in the stratagem was the need for the wind to be aligned in the right direction with where they wanted the gas to go. 

For example, what if the wind suddenly started to blow back In the direction of those who fired it? 

Aside from that, there could simply be easy counters to using gas warfare such as the masks and even a long and deep cave system could save Mark from getting overtaken by the white mist.

 Amidst the scuffle and pandemonium, Mark saw that Paul had suddenly begun to slow down in movements, taking more of his time. 

Looking closer, it seemed the body that the major was leaning over a dead body without a sound. 

That meant two things.

The first is that the major had found a mask. The second is that there was only one, and he wasn't about to share it. 

He weighed his chances. 

If he continued to look for a mask, there was no guarantee at all that he would find one. The major himself was nothing special, probably easy enough to handle if a solid attempt was made. What was problematic was the repercussions of doing so. What was the word again... mutiny? 

Either way, if he is caught, or if he somehow fails to get rid of Paul, he would essentially be dead. 

So he continued searching. 

There were a lot of bodies on the floor that were yet to be searched. He could still try to find a way there. 

Yet, he was also purposely, but almost unnoticeably approaching the major as he continued to inspect each of the bodies. The two options of searching and stealing were not mutually exclusive until the latter was actually done. For now, he still had a window of opportunity. 

Every few seconds, he was stealing a glance behind him. The gas was thankfully not showing itself quite yet, but worryingly enough, the sense of danger never left him. 

Mark tried a few more times as seconds began to seem longer than they were supposed to be, and stacks of dread weighed on his consciousness. 

And then the gas came. 

 Leaping into action, Paul swiped down on the body and took what was undoubtedly a mask off of it. 

At the exact same time, Mark jumped up from his previous action. It seemed like the two men were both right to distrust each other. 

After having taken the mask, Paul ran in the direction of the gas while simultaneously trying to hastily put on the mask. 

Mark stood still, reached into his pocket with trained efficiency, and drew a luger pistol that emanated chilling coldness. The apathetic feeling no longer felt so foreign as much as it was starting to feel innate. 

Somehow, he was allowed to keep the gun while joining the army. A memory flashed by his eyes as an unimportant figure told him to cherish the firearm as if it were his life. 

He aimed it at the major with deadly precision and fired. 

It hit Paul's neck, exactly where he wanted. 

A scream was muffled by the mask as Mark rushed forward and stretched his mind to pacify the wounded man with despair. It worked, and the screaming ceased. 

Ripping the mask off of the major's face, the young man's pale-black eyes glimmered in the gas as he put the bloodied lifesaving garment on his face. 

Meanwhile, the major turned around with utter horror on his visage.

"You... you aren't human." 

Mark strangled him to death.

It was easier with the poison gas. 

He then rose and walked out of the tunnel through the cover of the white gas. 

The man might not have deserved death, but he didn't care. 

All that he was now was a number. 

Another death to the cause of the nation.

Another death added to his personal count.