How did the lady in the following passage know her husband was dead?

She sent an assassin after him before entering the elevator; she assumed he was dead by that time but wasn't 100% sure, however, she did also add a time he should be killed, or she simply knows the assassin was on the job the moment she called him 1/2 hours before entering the elevator.

Her husbands life was hanging on engines, wich got turned of in 12 minutes- a guaranteed death

The power came back on and the doors opened and that is where her husband was lying there dead