Is there a kill button?

Basically, I've got a sequence I'm running in the middle of a live set, but when I press STOP, I want everything to stop dead. Unfortunately, the shorter samples (e.g drums) stop, but the longer samples play throughout their entirity, unless I press stop twice, and that sounds really messy. these longer samples have to be set as 'ONE SHOT' because I hit them once whilst triggering drums. Any idea how to make the whole sequence mute so I can trigger another layer from silence?

Make a mute group, and use an empty pad in that mute group (or alternatively, and empty pad with the other pads as mute targets)

If you still need to stop the sequence, then it's still easy enough to hit both the stop button and a pad simultaneously.

If you press 3 times STOP fast it sends "all notes off" cutting all sounds and midi.

yeah, 3 x stop is the best way to do this imo. it really is fast if you get used to it.