It was a gesture in keeping with his selfless action.
On waking from the operation to donate part of his liver, customs inspector Simon Hui Sai-man's first thought was for the health of the recipient, fellow officer Yuen Wai-cheung.
'After he awoke from the operation he kept asking about Yuen's progress,' said Professor Lo Chung-mau, head of the University of Hong Kong's liver transplant team who led the operation.
Lo said Hui was fine and had not thought about the risks and discomfort involved in the procedure.
The 40-year-old was taking liquids, while Yuen, the man who owes him his life, was reported to be in good condition and able to respond to his wife's voice despite being in a coma.
The two men, who did not know each other before the operation, were in stable condition in Queen Mary Hospital and were expected to be moved to general wards.
Yuen damaged his liver when he fell on metal railings during a raid targeting illicit cigarettes in Tseung Kwan O last week. His condition became critical on Tuesday and he needed a liver transparent urgently.