The Dunedin worker, who lives in the villa with Otago Polytechnic students, said it was his first year flatting and he was uninsured.
"I don't know what is going to happen,'' he said outside the cordoned-off flat yesterday.
Police said they wanted to speak to three males, possibly wearing white T-shirts, spotted near the flat and seen running towards Frederick St, about 12.45am.
Asked what he would say to those who started the fire, Mr Thom replied: ''You don't want to know.''
Neighbour Debbie Boeyen said she was in her room ''when I saw flashing behind my curtain, and thought 'Oh my god, what is that?'''.
''I came outside and saw a couch on the porch on fire ... I saw three young guys who obviously lit it and were standing around laughing, but as soon as I looked at them, they ran away.''
She rang 111 and watched in horror as the fire ''just took off ... it was massive''.
Police Otago Coastal area commander Inspector Jason Guthrie said ''without the quick actions of the neighbours who called the Fire Service, this property could have been burnt to the ground''.
''If it had been occupied at the time, the lives of those inside certainly would have been endangered.''
It was a busy night for firefighters, who attended seven callouts in just over two and a-half hours in the student quarter.
Fire Service East Otago area manager Laurence Voight said those callouts to ''reckless acts'' tied up firefighting resources.
''While we are down there, we might miss the opportunity to respond to someone whose life is in danger.''
Following the arson, three rubbish fires - two in wheelie bins - were lit in nearby Grange St.
A fire appliance from St Kilda was sent to the Grange St fires at 12.51am, but police stopped short of saying the incident was linked to the earlier arson.
In the Grange St incident, rubbish at the front of a house was set alight while the occupants were sleeping.
The occupants of a nearby property smelt smoke and found their wheelie bin on fire. Another wheelie bin was also set alight.
The Fire Service urged residents in the area to remove all excess rubbish, mattresses and couches to reduce the risk that fires could be lit, and for people to look out for each other, a message reiterated by police.
Dunedin city councillor Lee Vandervis told the ODT the arson was ''a bad look for the city, but it might finally prompt the authorities to do something, because it had been going on for far too long''.
''We need video surveillance. We need to stop this ... it is costing everybody, including the DCC, far too much.''
Dunedin Mayor Dave Cull spoke out against antisocial behaviour.
''We have a responsibility as a community and as community leaders to lead the way to curb antisocial behaviour and not to normalise it, couch fires being the obvious example.
''It is really important it is treated as abhorrent behaviour.''
Detective Sergeant Brett Roberts urged anyone who knew who was responsible for the fires to call him on 471-4800, or give information anonymously via Crimestoppers on 0800 555-111.