The funnier thing is that despite you and everyone else knowing that the radioactive cloud if released would irradiate all of the SAFEST central parts of Ukraine before hitting Poland, you still ask why Russia would be more inclined to trigger that level of accident than Ukraine.
Your logic has a hole in it.
Murder-suicide anyone? It is clear that the Ukrainian government is not working in the interests of Ukraine. Otherwise, they would have accepted Putin’s ultimatum in February with no fighting taking place, and maintained statehood.
It is clear that their country is over, what they are doing is trying to produce the most damage, destroying as many stuff and killing as many people as possible, just to spoil the Russian gains.