How to handle dual initiative mythic ability
I'm seeking suggestions on how to run a mythic creature with the dual initiative feat in FG with the combat tracker.
Dual Initiative (Ex)
The monster gets two turns each round, one on its initiative count and another on its initiative count – 20. For example, if the monster's initiative is 23, for its first turn it could make a full attack (and take a 5 foot step) at initiative 23, and for its second turn at initiative 3 it could take a move action and cast a spell. This allows the monster to perform two actions per round that normally take an entire round, such as using a summon monster spell. For the purposes of spells and effects that have a duration of a round or longer or trigger at the beginning of the creature's round or the start of its turn such as saving throws against ongoing effects or taking bleed damage), only the monster's first turn each round counts toward such durations.
Format: +21/+1; Location: Initiative.
I'm thinking about just putting a dummy NPC at the second initiative, but I'm wondering if anything screwy will happen because it isn't the turn of the NPC actually doing the attacking. And also, because the second dummy NPC won't be on the map.
Thoughts?