Troy Collings was a New Zealand businessman who cofounded Young Pioneer Tours, a PRC tourism company that specialized in tours of North Korea, and he is known to make false claims that it was safe as long as you followed local laws. This is the company the now dead Otto Warmbier entered the country with before getting arrested and tortured for accidentally pissing off the DPRK.

I suspect that in regards to Troy Collings recent death from a heart attack in 2020, he may have been assassinated by DPRK spies in collusion with the PRC based tourist company he founded by using drugs that induce heart attacks, all because a few years after the above-mentioned tourist death he may have realized North Korea is unsafe as the government is dangerously easy to piss off and that they may turn on you completely randomly when you least expect it, and thus he may have had plans to make a public statement about this and also shut down his company.

Possible aggravating factors to the suspected change in opinion was PRC atrocities against dissidents in relation to the Hong Kong protests as well as the Uyghur ethnic group, and the incident where the PRC itself wrongfully arrested the two Michaels.

Whether the PRC itself is involved in the guy's death might be a possibility.