Ships that pass at night

Modern day students of English will find it strange that we actually had to learn the basics of the language brick by brick. Starting out with simple verbs and nouns we graduated to adjectives and adverbs, learning to parse each sentence into subject object and predicate etc.etc. In the course of this education, we also had to learn figures of speech, phrases, idioms, metaphors and proverbs.

So thorough was this grounding that there are some idioms that remained indelible, one of them being "Ships that pass at night", signifying two strangers that meet in passing, acknowledging one another by a sign , never to meet again.

Very often, one tends to unburden oneself to a stranger knowing full well that one's secrets will remain well hidden. Which is why Lucky opens her heart to Shanti (P.119)

But are Shanti and Lucky ships that pass at night? Or do they have more interactions?