Just moments after leaving Sugar Cube nightclub, in Queen Street, the 23-year-old is seen in a nearby takeaway.
The footage, recorded in the Subway sandwich shop in Queen Street, shows Michael choosing his food and a bottle of water, before paying, and calmly walking out.
His father, John 52, managed to obtain CCTV film from the shop, where Michael was spotted, in the early hours of Friday.
Today his family has told how they are enduring a “living hell” since their son went missing.
Since he was last seen, Michael has not used his mobile phone or used his bank account.
His mother, 53, said: “We are going through a total living hell. I would not wish this on my worst enemy. We have not slept, we have not eaten, we are just waiting. It’s hell.
“Not knowing is the worst. I am constantly wondering where he is. I would do anything to get my boy back.”
Michael, an electrician, had been on a night out with friends but left the nightclub alone.
He was last seen on CCTV, near St Enoch Subway at about 2.30am on Friday.
He did not return to the family home in Gooseholm Crescent, Dumbarton.
Michael is said to have been seen acting “erratically” in the CCTV images.
His mother added: “Michael would not take drugs – he is very against that sort of thing, which makes me think his drink was spiked.
“We have been told he was acting odd on the CCTV in St Enoch Square. Apparently he was running around. As soon as I heard that I knew something was wrong – that’s not Michael.”
Mr Slaven has been looking for clues in the CCTV film he obtained from the Subway shop.
He said: “The CCTV shows Michael coherently ordering his food and paying. He has obviously been drinking, but is not paralytic or out of it.
“We need to see the CCTV from St Enoch Square to make sure it is Michael.
“That kind of behaviour is so out of character for him.
“He is a social drinker, he is not the type to go on a bender somewhere.
“As soon as I heard he hadn’t come home, I was frantic. I knew straight away something was seriously wrong.
“He has everything going for him – a good job, a lovely girlfriend, and money in the bank.”
Michael’s mother is urging him to contact the family.
She said: “I don’t want Michael to be worried that he has stayed away, I just want him to come home. Please come home, Michael.”
Michael, who has a brother Shaun, 20, and sisters Paula, 25 and Monica, 21, is about 6ft, slim, fair, with short brown hair and brown eyes and was clean shaven.
When last seen he was wearing a white T-shirt with a grey square emblem on the chest, olive green ‘chino’ type trousers and dark plimsolls.
Police said extensive inquiries are continuing.