Debuffs expire when:
1) the listed duration listed in the ability that inflicted them is reached
2) when they are removed by an ally (including self) who uses an ability that dispels debuffs (commonly referred to as cleansing)
3) when attacked with an ability that dispels enemy debuffs (Vader's culling blade, Boba's execute)
4) when effected unit is defeated
For expose and stagger, they also expire when they are triggered.
All those methods will give EP TM. I've tested them all.