Routine

A complex hazard usually follows a set of preprogrammed actions called a routine. Once triggered, the hazard first performs its initial reaction; then, if the PCs aren't yet in encounter mode, they should roll initiative. If they're already in encounter mode, their initiative remains the same. The hazard might tell you to roll initiative for it—in this case, the hazard rolls initiative using its Stealth modifier. After this happens, the hazard follows its routine each round on its initiative. The number of actions a hazard can take each round, as well as what they can be used for, depends on the hazard.