Lawyer John Bamford broke his silence on Thursday, answering speculation over the identity of the "chair man" who was shown approaching 20-year-old Mert Ney before his arrest on Tuesday.

He told Seven's Sunrise he was trying to get ahead of "what was going to eventuate" with people hounding him.

Ney is accused of killing 24-year-old Michaela Dunn in a Clarence Street apartment before allegedly stabbing 41-year old Linda Bo at the Hotel CBD.

Mr Bamford said he was getting lunch when he saw a man emerge from the side of a building "and I think he had the knife raised".

"I just grabbed the chair and, you know, went after him basically as best I could," he said.

"I had to get rid of my papers that I had taken for lunch to read so I had to drop them on my cafe, but the guy knows me there so I didn't worry about that."

Mr Bamford said he had no option but to act and the reaction to his bravery was "a bit over-egged".

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"What am I gonna do, go home and say I was there and I could have done something and backed away from it? I mean there was just, there was no option," Mr Bamford said.

NSW Police Commissioner Mick Fuller has described the men who helped detain Ney as "the highest order of heroes".

"They saved lives," he said.

AAP