I think non-lethal takedowns should be possible, but highly unreliable.
Go around coshing people in real life, half of them aren't going to fall, half of those that do are going to have brain damage, and a not insignificant portion of those are going to die. Try to do this with electricity, and it's going to be a similar gamble. It's why if you really need to stop someone fast you fill them with so many bullet holes that you're bound to hit something important or at least make sure the lack of blood pressure gets them sooner rather than later.
In the Elite setting, things would be even rougher. The therapeutic index for anything that has high enough stopping power to instantly incapacitate a person through a pressure suit, cannot be good. In the case of the zapper, unless that suit is made of something conductive--in which case an electric shock will just go around the person inside it, to no effect--the amount of power you'd need to get though the insulation would almost certainly melt a hole in said insulation, and your target, even if not killed by stopping their heart, would asphyxiate in short order outside on a world with a tenuous atmosphere, or be set on fire in a breathable atmosphere.
I know this is a game, but an always-successful non-lethal takedown cheapens the entire non-lethal concept, IMO. If you've got compunctions about resorting to violence, using violence should be a moral quandary that cannot be bypassed by high-fantasy means to make sure violence can succeed with no risk of serious injury.
How could this possibly get a PEGI rating under 18?
No !