When Diane wakes up from her nightmare, she tells Sam and Frasier "I just had the worst nightmare of my entire life." But after Sam leaves Frasier asks if she was having another one of "those" dreams, she answers "Yes, but it wasn't as bad this time."
Frasier should not discuss the progress of a patient with Diane. However, this occurs within a dream where the Sam and Frasier each demonstrate unusual behavior, which is entirely plausible in real life.
When Diane picks up the phone to call the police after Andy Andy leaves with all of the bar's money, the phone has no phone line attached to it.
When the power is out and the candles are lit, the absence of shadows from the candlelight reveal the set is really being lit by dimmed stage lights.