Worst move ever.
Leaving aside the possibility of killing people (including innocent neighbours) with the fire....
Even if Milo were fortunate enough not to arouse the suspicion of the Fire and Rescue Service Investigator or the police in the first instance, any insurance claim for arson would be routinely passed to a Special Investigator acting for the insurance company.
Any Special Investigator worth the name would establish the tenant problem because the legal paper trail which Milo has referred to is covered in standard background enquiries.
This would establish motive for the incident, so would cause a deeper investigation, in which the Special Investigator would gather further evidence, including the instruction of forensic experts to test for the use of accelerants, phone records, witness testimonies, CCTV, neighbour evidence, etc.
He would be interviewed formally about the claim and any holes in his story, his whereabouts, his alibi and motives would be picked apart.
There is a then a good chance that, after an investigation which could take months or years, the Insurers would end up declining the claim for fraud and passing their files to the police.
In England and Wales there is a dedicated branch of the police for financial crime such as insurance fraud, called IFED.
So... Milo would be left with no payout, a burned out shell of a property, the inability to get insurance for the foreseeable and the possibility of criminal proceedings for insurance fraud or arson or both.
It would make a bad situation infinitely worse.