He said that as he intervened the two men fell on to the main road – lying side by side on the ground, the knife still in the attacker’s hand.
“I just tried to keep him busy, get the knife,” he said, adding he “tried a few times to catch the knife”.
“I try to kick his arm, maybe he [will] drop the knife, but I find out [it] is quite dangerous.”
He later found his own hoodie had been cut, with two spots of blood on it, but he was uninjured.
While Asadian distracted the attacker, Shine managed to escape, his neck bleeding badly.
There was no-one else around to help, and Asadian said he backed off before seeing the attacker walk into the greengrocer’s next to the bus stop, as if he was a “normal shopper”.
Asadian followed, shouting a warning to the woman behind the till that the man had a knife.
He then barricaded the man in the shop with a shopping trolley, as a bystander called the police.
Eventually he decided it was too dangerous to leave the man in the shop, in case he attacked the staff, and moved aside.
The attacker then calmly walked on down the road, Asadian said.
When the police arrived, he pointed them in the direction the man had headed before waiting alongside another female bystander with Shine until an ambulance arrived. He said the lady was trying to stem the blood from the victim.
Shine was one of two victims who sustained serious injuries during the attack which began shortly after 11:15 BST on Wednesday.