Rule 383.2.c

The Condition of a Trigger is evaluated after a potentially inciting event has been processed.

• 383.2.c.1 If a Game Object has a Triggered Ability that is active in a specific zone, it is evaluated and subsequently triggered…
• 383.2.c.2 A Game Object will not be able to successfully evaluate its Trigger Condition, however, if it leaves the zone that its…

Official Core Rules