Subject 3 (or "Patient Zero") is a Test Subject for Trinity Corporation's experiments regarding 3 Pathogens (hence the subject's name). He is known for his frequent appearances at night on the Forest Bunker in which he was put there for containment, however, his apperances in-game are not by physical means, but instead, a scripted event.
It was tackled in Journal Entries that Subject 3 came from Kin (which is Apocalypse Rising's next map). To avoid Airborne Infections, he was transported from Kin to Amend by water using their Shipping Company sector. His arrival is prior to the events that surfaced on Kin, therefore, players could assume that Subject 3 is held responsible for the outbreak back at Kin.
During experimentation, Scientists notice Subject 3's behavior as it constantly changes, however, players find him to be sane due to the fact that he is aware of what's going on back at Kin, the experiments done unto him while he's awake, and the messages written in blood that are scattered around certain places on the Amend Map. This also proves that Subject 3 escaped Trinity Corporation's horrors. It may have been that 1 and 2 died during experimentation or may possibly be added later on.
Subject 3 is a Scripted Event in Apocalypse Rising. He does not appear via physical means, but instead, engages players inside or outside the Forest Bunker during the Night. Several players were able to encounter Subject 3, and explained what happened during the said encounter. Players would experience random Screen Shaking and hear weird noises (similar to what players hear when they are heavily damaged), until their screen fades to black and back in-game (it happens for a matter of seconds), removing their Hunger Bar, Thirst Bar, and the Health Bar. Later on, Red eyes appear on the screen while the screen fades to black again and again, and later on, vanish without a trace. Players could also hear Subject 3 growl in anger during the first appearance of the red eyes.
After the encounter with Subject 3, players will have 1% left of their Health Bar so it is recommended to let your patch-up immediately. If your Hunger and Thirst Bars are nearing its depletion, it is also recommended to eat immediately to avoid death.
Players did also Video the Encounter and uploaded it on YouTube. One player died during the encounter but the death was due to Zombies, however, the red eyes appeared on his screen with matching sounds.
Avoiding Subject 3
Subject 3 can be avoided before he could strike. If players notice their screen's shaking , hear the weird static noise, and see the TV's display turn Red (if you're in the bunker), it is best that players should vacate the Forest immediately. Failure to comply will result in Subject 3's strike.
Subject 3's appearance is sudden. As mentioned in SkateBored's Apocalypse Rising Guide:
"Subject 3 is a creature in the bunker in the Forest. He has a 30% chance to come out every third night, from midnight to dawn. If he attacks you, you will lose 99% of your health. You cannot kill him. Some players call him "Patient Zero". If the monitor in the bunker is red, he will come out that night."