You were on set with emergency! as you were casted there, but emergency! had a crossover series with One Adam-12, in which Kent McCord acted on that set, so often he came through the firehouse door to get to somehow.

You were in the dining room of the firehouse, Kevin(plays as roy DeSoto), Tim(Chet kelly), Marco(Marco Antonio), Mike(Charles stoker), and Randolph(John Gage), you guys were in character filming a scene, and in character Randolph got up and walked out the fire station door.

But at the wrong time, Kent came in through that door while they were filming.