When Frasier is arguing with Kate, he tells her he's going to land on her like a sumo wrestler. He mispronounces it and says "sumu".
Bulldog cowers in an unused office to avoid bumping into Kate. It was four o'clock in the morning, and Kate was at the station to meet with Frasier and Roz, but what reason could Bulldog have had for being at the station at that hour? Obviously Kate had moved his time slot, too.
After the insomniac caller hangs up, Frasier sends the show to commercial but when Roz enters the booth seconds later the "on the air" light above the door is still on.