We are talking about sysadmins and an event endangering uptime? Just call them and send them in. Nothing can stop a sysadmin when their uptime is endangered: https://xkcd.com/705/
Another option is to failover to the redundant datacenter in another country and route all traffic to it. Then disconnect network and power connection to the infected datacenter and wait until the UPS stops working (normally few hours or days). If you don't want to wait that long use military weapons like aerosol bombs (they implode buildings and caves and remove all oxygen and can also be brought in via air ventilation ducts, so no need to enter and no damage to the city accept maybe the datacenter missing.
