"Level A-Four, that's Aboveground Four for those of you who haven't been paying attention to Storinal nomenclature."
Eurrsk Thri'ag to the rest of Plague Group[src]

Level A-Four was an entire floor on the Scohar Xenohealth Institute. It was where test subjects and experiments were kept in a tiered security system. There were three tiers and on the outermost part, a warehouse for animal subjects that were deemed safe was set up. The next tier held more dangerous creatures and lastly, the inner chamber housed lethal viruses. It was rigged with a plasma bomb that would detonate in case the sensors detect a leak. This was to prevent a plague from breaking out in the city.

During Wraith Squadron's Mission to Storinal, a few of their pilots dubbed with the codename Plague Group, infiltrated the Institute to collect a sickness that they could infect the crew of the Hawkbat with. Doctor Ton Phanan ended up choosing Bunkurd Sewer Disorder as their choice.