violent taxi driver sweared and robbed me

I took a taxi today near Ampang park, just off the road side of Marine tokyo (building). I greeted the man and told him "Lorong Gurney please". He said "ok". After I got in and shut the door, He told me 10 RM. I said " its really near by, 5 RM is fair, and i made a motion to try to leave the taxi. He then said " ok,5 ringgit". Then near my destination, he was suppose to turn left . But he did not signal to the left. Then his car drove abit forward, so worried he might take the wrong way, told him to turn left, ..he didnt respond ( he didnt even flinch). so i told him to turn left again softly since i thought he didnt hear ;and he shouted " I know! Stupid! there a car infront. I told him " you didnt respond"? in a shock state. He shouted "fuck you!! fuck you, what can 5 ringgit do, YOu think i am stupid? GIVE ME 20!!!". he said it in such a shaken state, he look like he was about to stab me with a pen. I said stop here, paid him 20 and got off, in value of my life. then i saw there was just a policeman in a motorcycle 2 metres ahead. no wonder he didnt kill me, and it was probably the reason he stopped shouting.thank the policeman

More over all, i am young, and male, I have been shouted at before by red neck taxi drivers. but he look different he seems like a real criminal, if i could give an opinion, i am concerned about letting him loose in the public. I am concerned for the younger people who might be unfortunate to this taxi. especially young ladies. He really look bad. I donno how to help but , people of malaysia , especially younger women travel alone, never ever take a taxi.