Rootwise Survivor

If a creature's survival ability triggers but that creature is untapped when the ability begins to resolve, that ability won't do anything.

If a creature's survival ability triggers but the creature leaves the battlefield before the ability resolves, use its tapped or untapped status as it last existed on the battlefield to determine whether or not the ability will do anything.

Survival abilities (and other abilities that trigger at the beginning of your second main phase) will trigger at the beginning of the second main phase you take in a turn. They won't trigger during your third, fourth, or other additional main phases in a single turn, if effects somehow cause you to have more than two main phases.