Mystique was the leader of the Brotherhood of Evil Mutants who attacked the Muir Research Institute in search for Doctor Moira Kinross. Once found, Mystique tied her up so she could be interrogated by Destiny who knew about Moira's secret status as a mutant.
Sometime later Mystique became impatient with Moira after she told them if they were going to kill her they might as well get it over with. But Mystique replied that they plan to, but it wouldn't do much good if they would just have to do it all over again next time.
Destiny did her best to convey to Moira the importance of protecting mutantkind instead of betraying it but Mystique thought that she needed a little more encouragement so Destiny revealed that her precognitive abilities showed her that Moira's immortality was only going to be extended to ten lives, maybe eleven if she made the right choice. After finishing up with their task, Mystique stood by while Moira was killed by Pyro who incinerated her body with his pyrokinesis.