The saber throws in JO's cutscenes are fake, they are only animations, there are no saber trails...
To do it properly, you would make an NPC that's noclipped and invisible, and small, without a model. It's the dummy target. Take the NPC, tell him to target that NPC. ICARUS can change the NPC's fire mode to secondary. Do that, then use the command that holds down the fire mode for a number of seconds. After those seconds, switch everything off.