The pain was so excruciating it roused him from his sedated state.
Mr Yip Beng Harng was having a brain biopsy to find out if he had a parasitic infection called toxoplasmosis. Doctors had drilled a small hole in his skull and inserted a needle to extract brain tissue for tests.
He had also just completed his sixth and final session of chemotherapy for non-Hodgkin's lymphoma, a cancer treatment that left his immune system in tatters and opened him to opportunistic infections like toxoplasmosis.
"I do not know why, but it was so painful I stirred," said Mr Yip, a 38-year-old professional services consultant, of the procedure conducted four years ago.
All he could remember, before he lapsed back into unconsciousness, was the pain.
Then followed a 21/2-week coma, from which he emerged with new challenges.
As if having cancer was not bad enough, the lesions on his brain from the toxoplasmosis had left the right side of his body and his vocal cords paralysed.
Relearning the simple act of walking required intensive daily physiotherapy.
"I am not going to run (again) until I get my walking fundamentals sorted out," said the former recreational runner who was diagnosed with non-Hodgkin's lymphoma in 2013. This cancer affects a type of white blood cells called lymphocytes, which are part of the immune system.
Even though he can now walk unaided, albeit with a slight limp, he still has weekly sessions.
Mr Yip also needed weekly voice therapy sessions to speak again.
The infection also left him with lasting slight delays in his cognitive processing speed, he said.
The diseases not only wrecked his body but also had a lasting impact on his relationships.
Initially, his wife and parents told no one he was in hospital for cancer, but when his friends found out, several rallied around him.
A close friend from secondary school, Ms Serene Lee, 38, accompanied him to this interview with The Straits Times.
"I told him that I would accompany him whenever he needed my moral support," said Ms Lee, an executive assistant.
"Bad things bring people together," reflected Mr Yip.
At the same time, a few others have stayed away.
"I think they are afraid to face someone with cancer, because cancer is...something negative and they do not want to be around someone who is suffering," said Mr Yip, who does not have children.
Mr Yip, who has been in remission for three years, credits his survival to the efforts of his oncologist, Dr Freddy Teo of Parkway Cancer Centre.
But he reserves his deepest gratitude for the unstinting care by his wife and parents.
"My mother and wife stayed (with me) throughout the coma... my parents visited every day and they massaged my feet so the blood would circulate," he recounted.
To manage the cost of treatment, especially at private hospitals, Mr Yip encourages individuals to purchase an integrated healthcare plan on top of MediShield Life.
"Chemotherapy is very expensive," said Mr Yip, "and we had to pay for everything upfront, but we would get the cost reimbursed later from insurance."
Chemotherapy and hospitalisation cost Mr Yip's family an estimated $400,000.
Their hope is that in years to come, the only mark of Mr Yip's ordeal would be the one on his forearm: a tattoo of the word Survivor, to commemorate his first year in remission.
Learn about common cancers in Singapore with this interactive 3D guide. http://str.sg/anatomycancer
Tay Hong Yi