There's no %orig
in your _quitAppAtIndex
:, so it won't kill any app and may cause a respring (not reboot).
For my advice (not tested):
SBAppSliderController* switcherController = MSHookIvar<SBAppSliderController*>(self, "_switcherController");
for (int i = [switcherController applicationList].count; i > 0; i--)
[switcherController _quitAppAtIndex:i];
Hope this can help, and this is what I actually did in Slide2Kill 7.