Inquiries are underway, including a CCTV review to establish he man's movements in the time he was outside the facility.
Security at the facility has been beefed up since the incident, Webb said.
"While this person's exact movements are still being determined, immediate enquiries were conducted in the vicinity, which have not established any particular businesses or properties entered by the abscondee at this point," he said.
"The police investigation is at an early stage, and initial indications are that this person has absconded by exiting via a fourth story window and climbing down a makeshift rope, which is clearly an extremely dangerous act.
"This person has put themselves and others at potential risk and their actions were unacceptable. Wilfully leaving our facilities will not be tolerated, and the appropriate action will be taken."
