The Bad Queen uses mirrors to communicate with whoever she wants.
So you often see her calling someone ("Mirror, give me the Hunter"). You then see the called subject, who must answer by taking a mirror.
At one point, she's shown calling the Troll King. He is angered by how long it takes to get a mirror, and you can see that his nose bled because he was called.
This leads me to believe that if she calls someone, they must get a mirror or they suffer pain. But the nose bleeding tells me that it's not only mental pain.
Is the Bad Queen able to kill someone by calling when there's no mirror in reach or did the Troll King get the nosebleed from something else such as raiding the village or because of his outrage?
I've only seen 3 of the 5 episodes so far, but why doesn't she kill her opponents using this method? Plot hole or not possible?