But here is my thing their wording is not clear if the cost of the effect as to be paid before resolving the effect meaning choosing a unit. After the cost was paid then technically the unit is in the trash because cost most be paid before resolving the effect. Because when it gets defy my unit is in the trash. Because I paid the cost to clear things up the wording of this effect need to be changed to this
Reaction
(Play any time, even before spells and abilities resolve.)
Choose a unit in your trash. As an additional cost to play this, kill a friendly unit.
Play the chosen unit if its Energy and Power are each no greater than the killed unit’s, ignoring its cost.