The bio-scan system worked by constantly scanning the ARC by laser, detecting and identifying all and any people and other animal life in the building.
If and when the bio-scan detected a creature within the ARC, outside of the Menagerie, it would within moments initiate the ARC's lockdown procedure, sealing the entire ARC within minutes and cutting the majority of the power. It would also seal the room the creature was detected in airtight, and begin gradually sucking the air out to kill the creature by suffocation.
The lockdown was designed to be overrideable only by Philip; requiring a retinal scan, or outside override from Prospero Industries, to be lifted. Otherwise, lockdown was difficult to lift. However, Connor once managed to pull it off by accessing the original ARC's underlying system.
Following the escape of the Dracorex from the Menagerie, Philip decided to make a scanning program to protect people if and escapes or incursions happened again.
Abby, having a particular fondness for Rex, allowed the Coelurosauravus to roam free in the ARC. Unknown to her, Philip had Connor installing a new bio-scan security system, due to the recent Dracorex escape. The new system was to scan every room of the ARC, for any creatures and if it found any, it would lockdown the ARC, seal the room that the creature was in and deplete the air source to kill the creature within.
After the system was installed, Philip was on his way out of the ARC, but found Rex outside the menagerie. Philip tried to warn Connor to deactivate the initial scan, but the ARC entered lockdown and Philip and Rex were locked in the laboratory as the air inside was slowly sucked out by motorized fans on the ceiling. Philip was also displeased when he overheard Connor call him an idiot over the communications for not explaining the entire system to him.
Philip believed that he couldn't be saved, as only a scan of his retina, could lift the lockdown and there was no retina scanner in the lab. Philip was also unhappy that Connor was putting Rex's life ahead of his, and tried to tell Connor about New Dawn before losing consciousness. Connor managed bypass the systems firewalls using remnants of the original ADD ARC system and cancelled the lockdown. Luckily, medics revived Phillip and Connor managed to save Rex and he was put back with the Mammoth.
The bio-scan detected the swarm of Future Beetles and triggered lockdown.
Because they was no power, the bio-scan could not detect several Mutated Future Predators in the ARC.