He said he was confronted by a man who had run across the road.
"He threatened me if I didn't take him down to my store he would shoot me in the legs."
The witness said the man had his hand hidden inside one of his pockets when he made the threat.
During the exchange the man had asked him how many people worked in the Burger Fuel store, he said
"I exaggerated how many staff were working tonight, so hopefully it would put him off because I feared for the safety of my colleagues," the student said.
The witness said the alleged offender then walked into the Subway store and went straight up a male assistant standing at the till.
"I could see him talking to the young man at the counter, but I couldn't hear what was being said, and I immediately rang the police," he said.
The alleged offender was described as about five foot six or seven, aged about 25 to 30 years old.
Police said no arrests had yet been made.