A number of times, I've been clicking the buttons to activate this ultimate and it just won't activate. The icon turns dark sometimes when I press the buttons. I understand it not working while I'm stunned but when people are dumping the ultimates and I'm trying to run out of the AOE, I'm clicking it and it won't work. I've tested it and it seems like I have to stand perfectly still for at least one second before pressing the buttons and then it works.