Yeah. Vader was ignoring Jerjerrod telling him he had to wait, Jerjerrod shoved between him and the elevator, Vader objected, and the guards immediately leveled their pikes at Vader, which apparently surprised him, as he held off long enough to let Jerjerrod gasp out that it was at the Emperor's command.
Point is, their loyalty is to the Emperor. Anyone they're seconded to will know that. Forget it and think they're answerable to you at your peril.
Well apparently the story of what happened to the two guards when they tried to stop Yoda never made the rounds in the Royal Guard community...