'I kept saying, "Help me, help me." But no one did'

A man is stabbed on the bus next to you. The perpetrator has left the bus, walking slowly, with an eerie grin on his face. what do you do?

Guardian Unlimited | Special reports | 'I kept saying, "Help me, help me." But no one did': "Eventually the police and paramedics came. There was blood splattered on the stairs and the floor but there wasn't that much of it. I remember thinking at the time that I must have blood on my clothes, and looked at myself. I was wearing a white T-shirt and I'd been kneeling with him but it was just my hands that were covered in his blood. I heard a girl say, as he was being taken away in the ambulance, that she hadn't wanted to give him any of her clothes. I said, 'What, in case they got messy?' Her face said yes."