Detectives are trying to figure out what made a Swedish-American IT worker climb over the balcony of his inner Sydney apartment before he fell three floors and impaled himself.

The 37-year-old remains in intensive care in St Vincent’s Hospital in critical condition, more than a week after the incident at Surry Hills on November 4.

Police on Tuesday appealed for another man who may have witnessed the “horrendous” event to come forward with more details.

The pair had arranged to meet at the Brisbane Street unit using an online dating app. Police believe the man’s date stayed at the unit for a few hours.

Later that afternoon the IT worker was seen climbing over the balcony railing before his fall. Emergency services were called at about 4pm to find him impaled on a table leg.

“We’re very, very clear (his date) was in the apartment at the time of the fall,” Detective Superintendent Gavin Wood told reporters in Sydney.

“A number of people” have confirmed the victim appeared to climb over the rail of his own volition – but the rationale behind his life-threatening decision while his date was in the apartment has left detectives puzzled.

The mystery man leaves the building where the IT worker plunged from a balcony.

“For a young 37-year-old man, in the prime of his life, to be in an induced coma in a critical condition in a country he wasn’t born and bred in is horrific in anyone’s language,” Det Supt Wood said.

“The fall is horrendous – that’s the best way to put it. This man’s life has been significantly compromised. In terms of the enormity of it – I don’t think you can get much worse.”

The victim’s parents and brother have flown to Australia to sit by his bedside while detectives release CCTV images of the second man.

He is seen entering the apartment block wearing a black Nike “Just Do It” shirt, a gold chain, aviator sunglasses, long pants and black shoes and is about the same age as the victim.

He is believed to have left the building after the fall holding a Louis Vuitton duffle bag.

“That person is a witness, I want to make that very very clear,” Det Supt Wood said.

Police don’t believe the man had any direct involvement in the man going over the edge but he can “shed some light” on the rationale behind his date’s actions.

While they have access to the man’s image and online identity they have yet to firmly establish who he is, Det Supt Wood said, and are seeking help from the public.