True to their word, Treyarch has rolled out another Call of Duty: Black Ops 4 Blackout beta update, and it brings the modes first-ever event-based playlist called Fast Collapse. Fast Collapse makes the play area is constrained at twice the speed, and is just one of the three special events planned during the beta.
Source: N4G PC Call of Duty: Black Ops 4 Blackout Beta Update Activates Fast Collapse, Feedback Responses Listed