I've been toying with waves that the player can effectively disable with certain choices within my map. It was relatively easy to stop the generation of infected using Variables and conditions. However, even when the condition for the Event isn't met (and thus swarms have been shut off) two things happen. 1. The event still notifies the player in advance, and 2. If I have a countdown set, it begins ticking into the negatives as the swarm it heralds never arrives.