It's not a strawman, this was how the US built nuclear plants in the 70s. The folks looking for leaks were construction workers building Unit 3 of the nuclear plant, using a candle to test the newly-installed seal on the reactor building for leaks. Units 1 and 2 were already live. The fire spread through the cable ducts into the wiring for the in-use reactors, taking out both redundant sets of control and monitoring systems. (Which is of course a design flaw too and lead to much tighter regulations.) There's a reason we don't build nuclear power plants like in the seventies.