I think the safest course of action was to shut down, which might also have calmed Jafari down, and have a "quiet word in his ear". I'm not criticising the pilot as he was clearly scared and panicked and did what he thought was best to diffuse the situation at the time, I'm just saying I would have probably done things differently.
I have had a couple of similar experiences although things didn't get quite as extreme as in this case.
1st incident - landed in a farmer's field (from whom my pax had agreed landing permission) behind a couple of other helicopters who had already just landed WITHOUT permission. Farm worker starts running towards helicopters waving arms, clearly not happy about helicopters in the field. On this occasion I did take off again in sequence, however the man did not approach under the rotor disc or throw anything at the aircraft.
2nd incident - landed at a job site and during rundown a teenager appears in my 2 o'clock with a large rock in hand ready to launch. Luckily my ground crewman intervened before I got as far as jumping out to tackle the little lout, but I am quite sure had there been no groundcrew there and I had tried to take off again he would have lobbed the rock at me with possibly tragic consequences...