If I remember correctly, in current iteration of Blackout feature the Crystal should be protected from monsters while heroes run around reactivating reset points. I had 2 Blackouts in last playthrough, both times I behaved as if the description is correct.

First Blackout was successfully completed, but during second one the Crystal was destroyed. Taking sounds into account, by that bombarding bots, Razers. But I wasn't there to see if it's true.