For multi-cellular organisms the picture is completely different and it likely wouldn't matter nearly as much.
Unsurprisingly there are organisms that seem to preferentially strike (and mutate) in hospitals, but have they (yet?) selected for some special preference for, say, urban hospitals? I doubt it, though it would be cool (and probably frightening) if so. That situation would be more likely to evolve than the researcher case.
The most relevant situation would be where the environmental toxin is mutagenic. My uninformed guess is that adaptation to that environment would typically involve mechanisms to reduce susceptibility to the toxin's mutagenic effect, and, as in the case with other toxins, organisms so adapted would be out-competed in areas where the toxin is not present.
I guess we have examples in the microbes which have adapted to live in areas of high radiation, but I do not know how they fare elsewhere.
Update: D. radiodurans is an example, but it has been suggested that its tolerance is simply a side effect of a mechanism for dealing with prolonged cellular desiccation - another sort of environment where they do well.
https://en.wikipedia.org/wiki/Deinococcus_radiodurans#Evolut...
It’s also worth noting that early in earth’s history, it was geologically very active and thus resulted atmosphere with all kinds of extreme weather—including lightning storms.
I don’t know how likely spontaneous recombination is, but those two data points make it seem plausible enough that electricity may have had an important role in the development of life on earth.
If there is a natural laboratory for this, this would be it:
https://knowyourmeme.com/memes/some-of-you-may-die
But, to nitpicking, I guess you could say the selection came after the gene got recombined. Surviving the zap and was lucky enough to do the recombination still do nothing. The effect of the recombination, i.e. the expression of the foreign gene, is the interesting part. If it confers an advantageous trait to the mutant, that mutant get selected for in the game of life. If it doesn't, which is most often the case, it is selected against, and would be quickly removed from the genetic pool.
We do this selection quite often in the lab so perhaps it unconsciously leaked out in my phrasing.
While I agree with Dennett,* I don’t think agency is correctly ascribed here, unless you can find selection for locations of increased lightning incidence(!).
It’s more like “any survivors remain subject to natural selection, as did those unfortunates that did not survive”
* https://en.wikipedia.org/wiki/Intentional_stance