User blog comment:Gundam Legilis/Vytal Festival Tournament Speculations/@comment-4010415-20151012041735/@comment-3257939-20151014065234

Perhaps because it's where the CCT is located? That mark was seen in Volume 1 and by Volume 2, one of Cinder's main objectives was located in Beacon which is one of the reasons why she infiltrated as an student. Maybe the job in Beacon was already done when the Virus was sent?