Per 
Private Henderson took aim over a wooden crate. Shadows casted by two buildings on either side of him has contributed to low visibility, nonetheless he still had the head of a UIU Agent on his crosshair.
The Agent was oblivious to presence which was an advantage for him. Henderson remained a stag for the rest of MTF Kappa-47 "Wind Strikers" with their team leader leaving him on that door to watch for any one that might interfere.
Seems like those people has just arrived.
Pulling the trigger, the recoil made Henderson flinched. The suppressor on his rifle has prevented all noise from being heard and in a split second, he watched the Agent's head disappear in a spray of blood.
"Agent down!" A voice yelled. "I repeat, Agent down!"
A cold sweat trickled down on Henderson's left cheek. He could feel the sweat soaking his balaclava that he felt the urge to scratch it. As he did so, he crouched behind the crate with his back resting against it.
What have I done? He thought. He peeked again and heard feet hitting the pavement.
He hid again, staring at the brown open door. It was his first job. He was fresh out of the boot camp. Sure, his time with the Regiment had made him see combat more than once.
But the operation is not against the Al-Qaeda or the Hezbollah, but against anomalous things that defies the natural law of physics. Something that shouldn't exist.
The ex-SAS gulped. His saliva passing through his dried windpipe. He peeked again, only to see nothing but an empty alleyway and the noises were gone too. He reckoned, they must have taken cover, preparing to breach at any given moment.
Thirty six hours earlier, Site-9 had given them an order to retrieve an anomalous object under the possession of a group of a drug syndicate: Honrado Cartel.
It was unknown why or how did the Cartel got their hands on it in the first place. The head-shed is still working how that happened.
But it doesn't matter now. What matters is how is he going to keep these guys at bay.
At the slightest noise they made, Henderson's body was immediately fueled by adrenaline. Acting on instinct, he took aim and saw a UIU Agent on full combat gear as opposed to the other one he shot, only wearing a black suit and tie. His aim was directed at the Agent's semi-transparent visor and opened fire. His rounds smashing against the Agent's face plate, shattering it to million pieces followed by blood spraying out of his face. He fell down in a loud thud! and his buddies behind him immediately scrambling back behind the corner while firing retaliatory shots.
Three rounds punctured the crate. He was glad that the crate was filled with something solid. Wood chips and concrete dust flew around him. He took a peek and found himself a lucky shot: the Agent's foot is exposed. He fired thrice, causing him to fall, leaving his body exposed. Henderson wasted no time firing at him before taking cover.
More shots came at him. He could hear the men advancing. Reloading methodically, his hands worked faster as they should. He never felt like this before.
In his mind, Henderson was in a shocked state. He is uncertain whether the Agents he was fighting had anomalous powers or not. He was attached with numerous MTFs before that had fought against Groups of Interests with people capable of creating things his mind doesn't understand.
He struggled to insert the magazine inside the rifle and when it finally hit home with a click! he peeked again and fired while reaching for the open door. He heard a yell followed by multiple gunfire. The wall beside him was perforated in an instant. He fired blindly outside the building; another scream could be heard followed by an, "Agent down!"
He let out a sigh, sweat trickled again. He made a bet with himself that he was probably sweating like a pig by now. What made him ask is the fact that he got used to the gunfire that hearing it is just like hearing a car horns.
"Henderson, we're going to Extraction B. Pull out, now!" A voice yelled over the radio.
The back door leads to a room where he was in right now. It has a staircase that leads to the second floor and at west, a door that leads to the dining area can be found. He retreated to it with a brisk pace, flipping the table with the wooden surface facing the open door and hiding behind it. He unpinned a cylindrical grenade: a flashbang. He pulled the pin and tossed it in the door. Just in time, four people walks in and the grenade sets off, temporarily blinding the breachers. Henderson wasted no time as he peppered them with bullets before they could retreat.
Screams after screams had never made the situation easier. Deaths only made him feel guilty even more and seeing their bullet-ridden bodies makes him want to tear his hair out of frustration.
It's never your fault. He told himself as he glanced to his right where an opened wooden door shows a peaceful living room. He retreated to and made another turn to the right, leading to a kitchen. He turned to his left where he saw a closed door. Reaching for the knob, he turned it and headed outside. The rest of Kappa-47 was waiting there with their armored vans.
Once he boarded one of the vans, they sped across the road.
#
Private Henderson was staring at the green eyes of an ageing bald man. He was wearing a dark blue uniform without any decorations, patches nor even a rank.
"You've open up on a UIU Agent just because he's 'standing there?'"
"No sir," protested Henderson. "He sees me."
Who is he kidding? Henderson was certainly sure the UIU Agent sees him…but when he tried to remember it, it was quite the opposite. But what is the truth anyway? Nobody sees it but him.
"Well," The man stood up, using his butt to push away the silver metal chair. He turned to reach the door and before he left, he took one glance at Henderson. "Take a rest," he said. "It must be a long and tiring day."
"It is sir, indeed."
With the door shutting behind him, the man casted the lie detector test operator with an inquisitive look. The operator simply shook his head, no.
"We can't put him on court-marshall." The man said. "Stress has gotten to him and it made him lie."
The operator did not respond. It was either he doesn't understand the man or he just simply care.
"We let Private Henderson be with Kappa-47 for more missions and observe him while SCP-3349 is still inside him." He added. "Call Dr. Moore. He and I has something to discuss."