This thread started with a query about the phrase, 'evaporating into THE mists of coincidence'. There is a definite article there and therefore, the presence of a mist is already assumed by the speaker. The speaker never suggests not intends to suggest that THIS particular evaporation is what is causing the mist. I don't see anything in that sentence that implies that, this evaporation 'became' the mist.

Somewhere along the road, this phrase has been converted into, 'evaporation into mist'. And hence, all this scientific/semantic plausibility confusion. There would be no mix up, metaphorical or otherwise, if it is read as it originally was meant to read: evaporation into THE mists of coincidence.