scmJS docs

Kill Unit At Location

As Kill Unit, for the number of units of the type in the location.

Action 23 · Kill Unit At Location(Player, Unit, Count, Location);

Argument Takes Stored in the action
Player a player or group bytes 16–19
Unit a unit type, or one of the unit classes bytes 24–25
Count a number of units, 1 to 255, or All (stored as 0) byte 27
Location a location (Anywhere is location 64) bytes 0–3
Kill Unit At Location("All Players", "Men", All, "Lava");