it's your sister Cheryl!
I work for Petersen Games. AMA
No, it will. It's like when you have 3 Power and first Build Gate (Action: Cost 3), then Control Gate (Unlimited Action: Cost 0).
It's not that you can't perform actions when you're at 0 power; it's that your turn is skipped when you're at 0 power. But if during the course of your turn you happen to reach 0 power, you can still continue it with otherwise legal 0-cost actions (such as Abandon/Control gate, the 2nd part of Screaming Dead / HWMNBN, etc).
Adam is correct here. My wording in the OMR implies strongly what Adam is saying, although I admit I never clarified this actual point.
On page 23 it reads, emphasis added:
"If you have no Power left when it is your turn to take an Action, you are skipped."
Because it is certainly true that you can spend your final Power to Move a Cultist into an Area with an empty Gate, and then immediately Control that Gate, it must also be true that you can do what happened in the OP's situation.