It’s a bit different after WOM, two trigger conditions for the next wave, either 120 seconds or <10 clanrats and <10 slaverats alive; since 120 seconds is a long time, they are probably killing parts of the wave without dealing with the elites, allowing them to stack up.
“continue_when”,
duration = 120,
condition = function (t)
return count_event_breed(“skaven_slave”) < 10 and count_event_breed(“skaven_clan_rat”) < 10
end