Seegson Security was a private security force operated by the Seegson Corporation. One such team operated aboard Sevastopol Station, under the command of Jake Sinclair. When a lone Xenomorph was unleashed on the station by the crew of the Anesidora in 2137, Sinclair and his men abandoned their posts and formed a violent and dangerous group of survivors, realizing that their chances of survival would increase if they went rogue.
Seegson Security was a corporate security organisation owned by Seegson. They handled facility security and low-level policing. Several text/audio logs imply that Seegson Security ran the docks and provided customs, and it's also likely that they sold security services such as firearms.
Inadvertently starting the infestation
A security team led by Jake Sinclair operated on board Sevastopol in 2137. As stated by Dr. Lingard, Sinclair and his team were responsible for allowing the crew of the Anesidora on-board the station after one of the ship's crew members Catherine Foster was attacked and impregnated by a Facehugger and needed urgent medical care. This ultimately led to a Xenomorph infestation breaking out on the station when a Chestburster hatched from Foster.
Out of desperation, Sinclair and most of his team decided to go rogue and hid themselves in Solomons Habitation Tower, where they tried to seal off all access to the area by shutting down elevators, barricading doors and welding vents shut.
Colonial Marshal Waits wrote an archive log for Sinclair, requesting help in dealing with the infestation. In exchange for Sinclair and his team's full cooperation, he even offered to drop his investigation in Sinclair's involvement in the black market trade. Sinclair declined the offer, however.
Waits later discovered that Sinclair and his team were shooting civilians, raiding supplies, and taking other survivors hostage. An infuriated Waits recorded an archive log for Sinclair, angrily stating that "When I find a way to kill this creature, I hope to hell that it found you first."
Slaughter in the Galleria
After Waits and Amanda Ripley finally killed the Xenomorph, Ripley spotted from behind a security shutter several AWOL members of Seegson Security guards protecting a group of civilians in Galleria mall. The security personnel reacted with hostility to Amanda's presence, immediately firing at her although the bullets failed to penetrate the security shutter she was standing behind.
Amanda then made her way around the security shutter using an alternative route. Coinciding with the above mentioned special order, a group of Working Joes appeared and attacked the survivors just as Amanda opened a locked door leading to the mall. Exiting the store room she was just in, she walked into the mall and witnessed the androids brutally murder the civilians while the security personnel fired at the synthetics in a futile effort to regain control of the situation.
Ultimately, most if not all of the security and civilians in the mall were all killed, while Amanda herself slipped away in the chaos.
Attempting to contact the Torrens and the betrayal
Following the destruction of the Anesidora at the hands of Henry Marlow, Sevastopol's gravity stabilizers were badly damaged, and the entire station began falling into KG-348's atmosphere. Diane Verlaine sent a radio message from the Torrens informing anyone still on Sevastopol that they're able to pick up survivors. Several security officers accompanied by Sinclair himself headed out to Seegson Communications, intent on contacting the Torrens and hijacking the ship in order to escape Sevastopol Station. Sinclair was actually unsure about the chances of being rescued and decided to remain at the transit hub should the team take too long, thus forcing him to leave without them.
The team then split up into two groups: one guarding the comms facility while the other attempted to contact the Torrens from the operations center.
As Sinclair predicted, the team spent too long in comms. Sinclair then betrayed them by shutting down the power to the facility and taking the last tram back to Habitation; he later transmitted a sincere apology to the group but explained that "Once you started looking for a ship that'll never come, you broke with the plan."
Slaughter in Seegson Comms
Whilst traversing across Seegson Communications in order to reach the station's exterior, Amanda encountered the same group of Seegson Security officers, still intent on contacting the Torrens. Ricardo informed her of their plans. Although they are unable to board it currently due to comms being disabled, he warns her to stay clear of them.
Out of options, Amanda went outside the station to manually align its communications array so that she could finally contact the Torrens and request evacuation, avoiding the security officers in the comms facility and the security officers trying to contact the Torrens from the control room.
Amanda then went outside the station to manually align its communications array so that she could finally contact the Torrens and request evacuation. When she arrived back at the control center (having lost contact with Ricardo), she witnessed a Drone drop from a vent in the operations center, causing a brief decompression within the room and causing the security systems to shut down all exit routes.
Amanda then observed from the relative safety of the elevator processing lobby as the three guards in the room opened fire on the Drone, only to be killed by the creature. Once it had left the scene, Amanda headed down to the comms facility via a second elevator.
With the Drone in pursuit, Ripley heads further into the facility, where she discovers that Ricardo has been subdued by a Facehugger. Seconds later, the Drone appears, forcing her to move on. She then inadvertently leads the Drone to the rest of the security personnel in the lower levels of the comms center, where the team is massacred by the creature despite their firepower. Amanda manages to escape in the ensuing chaos.
Some time afterwards, Sinclair and his remaining team were ambushed by a pack of Xenomorphs who managed to breach the Habitation Tower. All of his comrades were either killed or taken by them, including his wife and children, while Sinclair himself was mortally wounded and later died from his injuries, but not before recording his final audio log declaring his remorse for his involvement in the Xenomorph infestation and how his actions caused even more deaths of the people he was supposed to be protecting, but decided not to.
It can be assumed that any security personnel not at the habitation tower when it was breached by the Xenomorphs later perished when the station plummeted down to KG-348 and burned up in its atmosphere.
Seegson Security officers wore white riot control gear including a white helmet with a translucent face shield and a matching armour vest, both with the word SECURITY written on them. They also wore white, light blue, or black shirts with a Seegson Security emblem printed on the sleeve - as well as grey, blue or black cargo pants with a belt around their waist. For footwear, they brandished black boots or white sneakers.
Behind the scenes
Originally intended for the game were 'Seegson Private Guards'; various guns for hire that served as additional security and protection for those who could afford their service. Like Seegson Security in the main game, members of this security force were also going to go rogue and "become a law unto themselves" (as stated in The Art of Alien: Isolation), with the Colonial Marshals being "too few in number to impose any kind of order." They notably carried fully automatic firearms in conceptual artwork, something that was also completely cut from the game.
Every Seegson Security member Amanda encounters on Sevastopol is hostile. They are equipped with either a .357 Revolver or a 37-12 Gauge Pump Action shotgun. Their body armor makes them more resistant to damage but they can still be killed rather swiftly.
As with other hostile survivors on-board Sevastopol, if Amanda is spotted from a distance, the security guards will give her a chance to leave. If she refuses they will open fire. If they encounter Amanda much closer, they will open fire immediately.
- Two Seegson Private Guard suits can be found in the Colonial Marshal Bureau, possibly indicating that the Seegson Private Guard still exist in-universe despite their removal.
- The Seegson Private Guard's guns are still referenced multiple times within the files of Alien Isolation as "SMG", hinting that these characters were taken out of the game quite late into development.
- Oddly, some guards' shoulder patches have the San Cristobal Medical Facility emblem, though it's possible that they looted this clothing from other survivors.