The 16 Seconds of an SI Wave: From Countdown to Anti-Bait
The 16 seconds restart after kill observation. They are not the gap between waves. A healthy clump that stands still can hold the wave with no cap.
Two systems, two responsibilities
The tier changes both spawn control and AI. infected_control owns kill observation, the 16-second countdown, Anti-Bait, and spawn points. The AI layer owns post-spawn fighting. This page is only the spawn layer.
How the timeline runs
- Wave starts：Fill the normal spawn queue and enter this tier's kill-observation window.
- Start the countdown：If the queue is empty, live SI are at the low-pressure threshold, the team is healthy, and there is no Tank pressure, the countdown can start early. Otherwise it waits for the tier check time.
- Wait the full 16 seconds：This countdown runs on its own. The last SI spawn time cannot offset it. Fewer SI on the field will not shorten it again.
- Check for holding near the deadline：Anti-Bait can take over only in the last 4 seconds. A healthy clump that stays stalled for 2 seconds enters an uncapped hold at the deadline.
- Release the next wave：No hold means the wave drops at the deadline. During a hold, 2 seconds of progress, breakup, isolation, or a vulnerable state releases it immediately.
How Anti-Bait detects holding
It does not watch one person standing still. It watches team progress, grouping, and vulnerability together. Spread out but not moving prepares a break-hold wave. It will not enter an uncapped Hold.
- 12-second stall observation window
- Progress uses the team's lower-median Flow. One fast runner cannot stand in for the team.
- 4-second arming window
- Pressure can begin only during the final 4 seconds of the base countdown.
- 2-second hold confirmation
- Healthy, at least two valid survivors, stably grouped, and still stalled.
- 2-second release confirmation
- Stable confirmation after progress, group breakup, isolation, incapacitation, ledge grab, pin, or invalid Flow.
What counts as grouped
At least two valid survivors. One connected group, nobody isolated past 1200. Max span at most 800, or at most 1500 with average nearest-teammate distance at most 800. Down, ledge, pinned, dead, or unreadable Flow all count as vulnerable.
Why two waves sometimes come almost back to back
This is the most-asked question: it says 16 seconds, so why does the next wave seem to arrive the instant you finish the last one? Because the countdown does not start when the previous wave spawned — it restarts after the kill observation window ends.
An example: a wave spawns and it takes you 20 seconds to clear it. The countdown is not running during those 20 seconds — it waits for the kill observation window to close. Only once you are done do the 16 seconds begin. From where you stand, that wave took 36 seconds.
The other way round: if a wave is wiped out the moment it appears, the observation window closes quickly, the countdown starts at once, and the next wave lands 16 seconds later. Same 16 seconds, completely different feel.
Keep these in mind while playing
- Holding to heal is fine. A healthy clump grinding in place holds the wave until you take a step.
- Progress is lower-median Flow. One person running ahead does nothing.
- A down or ledge grab dumps the wave immediately. Do not stand around the downed player too long.