Gamestate:
I have The Wandering Emperor on board
I activate the -2 ability to exil a tapped creature
My opponent only controls a tapped Graveyard Trespasser.

In this state my game kinde stopped and my timer runs out.
I suggest that the ward trigger goes on the stack or the game asks me to confirm the target for the wandering emperor (even their is only one legal target).
Neither happend. I was forced to watch the timer run out while nothing happend.
I wasnt able to activate another ability, tap a land or cast a spell.
After some time I was returned to the main menu.