I was watching an anime and I got stumped on this sentence (Context: the speaker is an old man character explaining the concept of soulmates). "運命の人同士が出会うとき全身にビビーンと衝撃が走りたちどころに互いを好きで好きでたまらなくなる" The part that confuses me is the 走りたち. From what I know, you can only attach the plural suffix たち to nouns, specifically human nouns. And it's less like a pluralizing suffix and more like a "noun + and company" phrase. So what's it doing after the i-stem of a verb? I think putting verbs into the i-stem makes them into nouns, but that doesn't really makes sense of the sentence. What's this たち supposed to mean here.
1 Answer
That is a case of incorrect parsing. It is not 走りたち+どころに but 走り+たちどころに. However, note that たちどころ starts a new clause. So the sentence can be broken down to [運命の人同士が出会うとき全身にビビーンと衝撃が走り][たちどころに互いを好きで好きでたまらなくなる]. A comma right there may have helped you parse that.
Now for the word. たちどころに means "on the spot", "instantaneously". The translation would be something like "When those who are fated meet each other, a shockwave runs through their entire body, and on that spot, they will not be able to resist loving each other."
