The sky was red when he woke up from his stasis.
Although he was frequently assigned this color, 60 didn't like it.
It looked to much like blood. Hank's blood.
He saw himself again in that tower, threatening Hank to stop 51 to convert the androids from Cyberlife's storage.
But 51 didn't stop. And 60 had to shoot.
Red was everywhere. It mixed with blue soon enough.