Having read up on the Sacrifice talent recently, it struck me that there's no actual limitation set as to when you have to use the prepared sacrifice; beyond it taking a Full-Round action to kill them, once the preparations have been made, provided nothing would occur that would counter the previous efforts made on the part of the sorcerer, there seems to be no indication that they must be used right away.
While I'm sure most right-thinking GM's would quickly put the kibosh on players who stroll around with a wagon full of pre-prepped sacrifices for when they want to use psychic powers, it does introduce some potential combos that may occur between the preparation of a sacrifice and the use of the psychic power that will utilize them. For example, a sorcerer could potentially set up a sacrifice ready to go, then use Boon of Tzeentch for extra Psy rating, Protean Form for a boost to Unnatural Willpower etc., THEN kick off some hideous Pushed power with a grossly inflated Psy rating that they would largely avoid the drawbacks of, since the sacrifice is the one taking the brunt of it (you'd still suffer the effects from Boon of Tzeentch though).
Do you guys feel I'm misreading the talent, or interpret it in another way?