"It was a pretty quick incident, so he got in and demanded the drugs he wanted - he didn't get them all - but he was in and out within a couple of minutes."
The nurse was left very shaken and upset following the ordeal, Mr Lloyd said.
But she was able to pass on to police a clear description of the man.
The clinic had been on Tasman Street for 50 years, and Mr Lloyd said that in the seven years he had been there it had never been robbed.
"We are gutted, [but] we're really happy that [for] the nurse in question, it was over and done with without any violence done to her."