Angry that a taxi driver had taken his photograph without his permission, a staff nurse snatched the cabby's mobile phone and punched him while they were inside a lift, a court heard.
When the lift door opened at the 11th storey, Mr Tan Kok Peng, 59, tried to get his phone back.
But Arey Lauren Loretizo Dela Cruz, 31, threw the phone over the parapet and punched the cabby hard on his left cheek.
He then rained blows on the victim's face.
Mr Tan crouched on the floor in pain and covered his face to protect himself.
Dela Cruz fled the scene by taking the stairs.
Mr Tan then headed downstairs as well.
Although it was 4am, a few people who were in the area helped Mr Tan to locate Dela Cruz, who was at a staircase landing in the block.
Police later arrested the nurse.
Dela Cruz, who had pleaded guilty, was yesterday jailed for five weeks for causing hurt to Mr Tan on Aug 27 last year.
He has compensated his victim to the tune of $1,338. Mr Tan needed seven days' medical leave for multiple bruises.
Deputy Public Prosecutor Teo Lu Jia said that Mr Tan had picked up Dela Cruz at Orchard Towers at about 3.30am on the day of the incident.
Along the way, Dela Cruz vomited in the back seat of the taxi.
When Mr Tan arrived at his destination, in Simei Street 2, Dela Cruz exited the vehicle without paying the taxi fare of $23.
Mr Tan got out of his taxi and asked Dela Cruz to pay up.
He asked for $30, inclusive of the taxi fare, to have his taxi cleaned.
When Dela Cruz found that he had only $10 in his wallet, he told Mr Tan to go with him to his unit so that he could get some cash.
While the two men were in the lift, Mr Tan decided to take a photograph of Dela Cruz in case he decided to run away.
That was when Dela Cruz attacked the cabby.
The maximum penalty for causing hurt is two years' jail and a $5,000 fine.