It had to be a power failure of some kind.
But just as they are about to leave, there is a power failure!
They were for use in the event of a power failure.
The power failure was the latest in a series of problems at the hospital.
"I guess it would be bad if all of them went down at once, in a power failure."
He must have followed him up and come in immediately before the power failure.
"Power failures are following them every step of the way."
There was a power failure and the lights went out.
But one must file within 30 days of the power failure.
But what came up on the screen showed no power failure.