Crawling forward through the air duct, the assassin felt the slight hum from fans several floors underground. One wrong turn and it was a dead drop into those spinning blades. It would be an unpleasant way to end. He focused on the path he was to take, moving forward on elbows and knees. He had gone maybe ten metres when he passed another vent and heard voices.
"There's someone in the tower! Get the Salarians out of here! I want this place locked down!" It was a radio communicator, and a second voice, this one just under the vent, quickly responded,
"Should we give them a few minutes or-" He was cut off,
"No! Get them out now! Send the mechs after them if you have to! I want them gone!"
The assassin didn't bother waiting to hear the reply. The mercenary would follow orders and turn the robotic security drones on the Salarian workers throughout the tower. He closed his eyes for a brief moment. This was his fault. Silently, he said a prayer to Arashu, goddess of motherhood and protection, asking that the Salarians make it out alive before the mechs started shooting. They were innocent in this, and their deaths would be on his conscience. Or they would have been, had he been expecting to make it out alive. He continued along and up the duct, now aware of the sounds of gunfire below.
Several minutes later he paused again, this time aware of a merc approaching the vent nearest to where he was moving.
"I think he's in the ventilation shafts!" The mercenary called out, informing a second guard if the assassin's presence, while simultaneously pulling off the vent cover, "I'm going to go take a loo-" He didn't get a chance to finish his sentence as the assassin pulled him up, neatly and efficiently breaking his neck as he did so. A quick burst from his gun took care of the second guard. Leaving the one body outside the vent where it had fallen, he pulled the first mercenary over to the nearest drop and pushed him over the edge. That's when he saw them.
The glance that he caught was so brief, there was no way that they could have spotted him, but he was nonetheless shaken. One floor down, three people had been standing, peering up into the shaft from which the mercenary's broken body had fallen. They were not Eclipse mercs. Quickly, he went over the details in his mind.
Three people. One Turian, male, two Humans, female. None of them wore a uniform from a mercenary group that he recognised. The one human had been hooded, her face obscured by shadow. The Turian was badly scarred, the right side of his face damaged. The second human wore armor with the N7 insignia on the right of the collar. She was Human Alliance, Marine Special Forces. What was she doing in Dantius Towers, and at the same time he was there? This was too much to be a coincidence. It looked like he was to have some competition. Then he paused for a moment; competition, or were they there for him? He quickly continued on up through the vent, pushing towards his goal with renewed purpose. This was no longer a simple matter of getting to Nassana Dantius to kill her – he now had to beat a team of operatives led by an elite marine, and he had no intention of not completing the job. It was time to step up his game.
Reaching the next floor, he kicked out the vent cover and vaulted down to the floor, keeping a careful watch around him for mercenaries. He held his sniper rifle in the ready position. He would rather avoid engaging in a fire fight before it was necessary, but he was nothing if not prepared. Hearing voices nearby, he froze, listening,
"Oh gods, oh gods, Shelum!" came a frantic whisper, "We're going to die! We're going to die!" The first voice was quickly hushed by a second – Shelum, the assassin presumed,
"Quiet! Are you trying to get us killed? If anyone finds us…"
The voices were coming from a storage room, not far to his right. A quick visual sweep revealed no immediate dangers, so he stepped towards the door and opened it.
Inside were two of the Salarian construction workers, huddled together, hands up to protect their faces. He regarded them for a moment, before ordering,
"Stay here. I'm locking you in. Someone will be searching this facility come morning, and you will be let out." With that, he closed the door and bypassed the locking mechanism, both sealing the Salarians in and the mercenaries out. At least two innocent lives would be spared tonight. He returned his focus to the task at hand, and his next destination: the elevator. It would be foolhardy to use the actual elevator car, who knew what manner of heavy weaponry might wait within, and he was only one man, but the elevator shaft did not yet have all security systems functioning, and so made for easy access to the upper floors. It was just a matter of entering the corridor at a set of doors that the elevator was not present at, and avoiding being crushed by the car if it were to pass by him. This was the reason for the harness he carried with him. While he was perfectly capable of making his way up the elevator shaft without the use of technology, should the car pass by him, he would be forced to let go of the handholds and swing to the side. The harness would enable him to do so without the chance of missing a grip and plummeting to his death. Simple, in theory. He hoped that he would not have to test it out in practice.
The first step was to ensure that the elevator would not be on the same floor as the one that he was entering from. This was simple enough; he had a small piece of material kept in an airtight vacuum container specifically for this purpose. A chemical compound developed on his homeworld of Kahje, upon first inspection it appeared to be nothing more than a hand-sized piece of plastic. For all intents and purposes, that was exactly what it was. Its beauty lay in the unique properties of the chemical it was comprised of. In a vacuum, it was solid and sturdy. Expose it to air for more than a minute and it began degrading, sublimating until it eventually disintegrated entirely. This was how he would ensure that the elevator would stay on this floor until he reached the shaft one floor up. He would have to move fast, but moving fast was what he was good at. The biggest risk lay in calling the elevator to the floor he was on. There was no guarantee that it wouldn't be full of armed mercenaries, or the commandos from downstairs. It was a risk he had to take. He pressed the call button and returned swiftly back around the corner from which he had come, rifle trained on the door. Several moments later, the panel turned green, and the doors slid open, revealing two Eclipse mercenaries, weapons drawn. The assassin squeezed a shot out before the pair had even registered the door opening, dropping one merc instantly. The second guard, a young Asari woman, turned to her fallen comrade, a look of shock flitting across her face before she, too, was down. The assassin moved out from his hiding spot and did a quick visual sweep. Both women were dead, two good, clean kills. He expected nothing less from himself. He had been taught from the very beginning to end suffering in his targets as quickly as possible. There had only been one violent day when he had disobeyed this rule, and he still felt shame in remembering it. He lapsed into memory recall before he could stop himself. Two sets of eyes look up at him, pleading - "Please," the Batarian rasped, "Just kill me!" - "Like you killed her?" the assassin asks. He shook his head, back in the present. That was definitely not a memory in which he wanted to get lost. Satisfied that the bodies were not blocking the elevator door, he removed the vacuum container from a pocket in the long grey coat he wore. A quick twist and there was a hiss as air rushed in. He took the Solugel cube and placed it against the edge of the door, in a place that would ensure it would hold the for open until it dissolved, then he was off again, back to the air vent. He made his way swiftly up to the next floor, aware that he only had about three minutes before the elevator doors would close. He likely had more time, as it would not move until called to another level, but if he had made a habit of betting his life on "likely" he would not have made it to fifteen, let alone past thirty.
One level up, he hopped out from the vent cover, and was making his way to the elevator doors, when he heard the telltale swish of a door opening somewhere behind him, followed by raised voices,
"Hey! What are you Salarians doing in here?" It was a mercenary, obviously he had come across another group of the maintenance crew hiding from the gunfire. Obviously terrified, one of the Salarians started pleading,
"Please, we just want to go home! We haven't done anything! We-" He was cut off by the mercenary,
"I've heard enough. Nassana wants you out of this tower, and she doesn't care if it's dead or alive. Now, which one of you would like to go first?" The assassin had heard enough. Sprinting down the hallway, he rounded the corner just in time to see the merc standing inside the doorway, pointing his pistol downwards towards a cowering Salarian. No time to lose, the assassin pulled his rifle up and shot, pinning the mercenary in the back of the skull. Before the mercenary's comrades even realised what had happened, he broke the second one's neck, and shot the third square between the eyes as he spun to see what had happened to his friends. The assassin didn't have time to check on the Salarians, and hoped that they would have the good sense to shut the door and stay hidden. He jogged back to the elevator, and bypassed the safety lock on the doors.
Below him was the car, still stalled a floor down. It would have been much simpler to wait on the top of the elevator and ride it the whole way up, but that would be relying on the off chance that it would be going to the top of the shaft within the next several minutes, and he wasn't willing to wait that long for something that might not happen. The assassin was the best, though, quick, graceful and alert, and had carefully studied the blueprints, giving him the edge that he needed to safely traverse the inner labyrinth of corridors, ductwork and passageways of the towers.
Hooking his harness to an electrical cable to the right of the inner doors, he swung himself into the chute, ready for the long ascent. The harness that he connected was a clever piece of technology, allowing him to move up freely, the loop that attached him to the cable would engage and lock down if he fell more than a foot. Should the need for a speedy descent arise, he could simply press a button, and he would be able to repel freely downwards. His equipment properly connected, he began to climb.
He was fast, agile, and confident in his ascent. He had not always been comfortable climbing. The world from which his people had come had been mostly arid desert and plains, and while it had been two centuries since his kind had lived there, some things were hardwired into the brain. His training had been overcoming that initial hesitation, and moving towards a place where he did not feel fear. Now, if an outsider were to look at him, it would seem to them that he was in his element, hands grasped around a cable, shimmying his way upwards. He got a rhythm going, and soon he was making excellent progress. It would not be long before he could leave the chute and head for the bridge, his target, and, ultimately, his death. It brought him a sense of peace, knowing that it would be over soon.