So the plasma pistol doesn’t have the emp effect with previous halo titles with the exception of halo 1 and 2. It could be reworked to malfunction vehicles this could be done by inverting controls. If a team on warthog is driving off with a flag, you could shoot a plasma round the driver would accelerate but reverse to that outcome.
It could also apply to aerial vehicles making ascend become descend, though I’m sure pilots could quickly adopt. If they were to be hit with a shock rifle and plasma shot could have could be fatal. I’m not sure if this could be done in forge but some creations already have been amazing and complex.