This actually happened to me, except it happened on the bus, this creep kept chatting to me but things turned decidedly nasty on the bus and through pure fear all I could do it get off as soon as possible and pray he wouldnt follow me, he did so I ran off the bus and into the first big company I could see. (there was only businesses)
I went in there and explained, I was shaking and scared, not because he kept trying to attack me on the bus but because he followed me off !
I was in too much shock to shout at this guy, fear can be quite crippling, I kept protesting but not actually screaming or shouting...