Really scary. For those unaware of how badly this kind of situation can end up, read about the horrific Goiânia incident in Brazil.
https://www.npr.org/sections/thetwo-way/2013/12/04/248737662...
How much is 300 curies?
A mole of cobalt 60 weighs 60 g, so it was a quarter of a gram if I did the calculations right.
The ln 2 factor is because the probability of a decay happening in a second is ln 2 divided by the half life.
Or 5,2 years
> Four months before the theft, on May 4, 1987, Saura Taniguti, then director of Ipasgo, the institute of insurance for civil servants, used police force to prevent one of the owners of IGR, Carlos Figueiredo Bezerril, from removing the radioactive material that had been left behind.[7] Figueiredo then warned the president of Ipasgo, Lício Teixeira Borges, that he should take responsibility "for what would happen with the caesium bomb".[7] The Court of Goiás posted a security guard to protect the site.[8] Meanwhile, the owners of IGR wrote several letters to the National Nuclear Energy Commission (CNEN), warning them about the danger of keeping a teletherapy unit at an abandoned site, but they could not remove the equipment by themselves once a court order prevented them from doing so.[7][8]
> In light of the deaths caused, the three doctors who had owned and operated IGR were charged with criminal negligence. Because the accidents occurred before the promulgation of the Federal Constitution of 1988 and because the substance was acquired by the clinic and not by the individual owners, the court could not declare the owners of IGR liable. One of IGR's owners and the clinic's physicist were ordered to pay R$100,000 for the derelict condition of the building. The two thieves were not included as defendants in the public civil suit.
I'd consider it very likely it wasn't moved for 2 years because the director pulled some strings to make sure it'd stay there, consequences be damned