But the course he devised at Carlisle College has so far trained 150 doormen and women. The training has fostered a trusting relationship with the Cumbria Constabulary and helped reduce violence on the streets.
The National Certificate of Further Education course - which carries the almost politically correct title Door Supervisors, Not Bouncers - has now been snapped up by training providers nationwide. It recently received a Further Education Development Agency award as part of adult learners week.
It began two years ago after Carlisle City Council approached the college to solve the problem of fighting outside clubs. Carlisle's doormen had an image problem.
"There was a perception that some of the guys got the job because they fancied a bit of aggression," says Mr Gentry, the college's industrial liaison manager.
One would think there wasn't much to being a bounc ... sorry, door supervisor.
Surely you just stand at the door wearing lots of jewellery, look mean and stop people with the wrong shoes getting in?
Not so, says Mr Gentry. During the four-evening course, trainees cover the legal aspects - the right to search people and how to search, what is reasonable force and so on. They learn the basics of resuscitation and how to put somebody in the recovery position. The police teach them how to identify particular drugs and show them correct restraint techniques.
The half-hour multiple choice exam, in which students must score 70 per cent to pass, has questions such as: "You see a customer smash a cigarette machine by deliberately kicking the glass. Do you have power of arrest?"
On race relations issues students wrestle with questions like: "A West Indian man assaults a manager of a pub. The manager then issues instructions that no West Indian men are to be allowed inside the premises because they cause trouble. Is this lawful?"
Mr Gentry admits the course has been a form of public relations exercise. But is it producing a better breed of bouncer? Sergeant Vicky Ritchie, whose patch includes the city's main clubland, believes so.
"It was an us-and-them situation between the police and bouncers. There was this absolute lack of respect on both parts. Now a lot of these barriers have been broken down.
"We say they're the police inside the club, we're the police outside."
Buskers Nightclub in Carlisle employs a team of 25 door supervisors. Manager Andrew Gardiner says the course has helped weed out the thug element.
"In certain outlets people were getting beaten up. It has stopped a lot of that," he says. "Now we can't employ anybody who hasn't been on the course - it's laid down by the city and the police.
"We now know who we're employing and that they have been trained in the right way.
"Everybody thinks a door supervisor is a bouncer. That's not the case anymore."