Zone event

Zone events start inside Harder Zones, zones with players in them one at a time, and last up to 30 minutes. It can one of these:

Clear 4 waves. The last one brings a Boss. From the second wave on, a wave can bring a twist: Berserkers (when one dies, zombies near it start sprinting), Amplifiers (five times the health), or at night a wave of Sprinters.

Kill the Boss, shown on the map, and it's escorts. It has to die inside the zone. Whoever kills it, gets a Gold Chest.

A wave of zombies inside one building, in the zone. Kill them all.

Stand within 8 tiles of the spot on the map, ringed on the ground, for 5 minutes in all. Only your time there counts, not kills.

1:15 for Bronze
2:30 for Silver
4:30 for Gold

4 waves and a Devourer. Every corpse it eats, takes 30 seconds off the clock. Kill it as well as the waves.

Silence all 4 Screamers, shown on the map. Every zombie you kill in the zone counts, and a Screamer kill is worth Bronze on its own.

Everywhere but, Hold the drop, your kills decide your chest:

5 kills for Bronze Chest
15 kills for Silver Chest
30 kills for Gold Chest

Every chest holds 10x Money Bundle
Plus random loot: 1 roll for Bronze, 2 for Silver, and 3 for Gold.
The top killer gets 1 more roll.
Whoever kills a Boss or the Devourer gets 1 more roll.

Theoretically, depending on the event, you can get 5 chests. By getting gold for killing 30 zombies, Being the top killer, and killing a Boss or Devourer. The only event where this is possible is Bounty, Feeding frenzy, and Waves.

On Hold the drop event, the most rolls you can get is 3. There's no top killer and there's no Boss or Devourer to kill. So your chest rolls depend on how long you are in the circle.

The loot can be:
AmmoCan
Firearms Cache
Food Cache
Hayes Cache
Industrial Cache
Maintenance Cache
Medical Cache
Military Cache
Preserved Food Cache
Survivor Box
Weapon Cache

You'll get no chest if time runs out, or staff stops the event. A zombie that vanishes comes back near you.

Chests wait for you, even when you log off. Click the chest on your screen to open them.