inquire about
闖 centers on the act of inquiring or looking into something, often with a sense of entering or intruding to seek information.
闖 combines 門 (gate) with 馬 (horse), suggesting a horse entering or peering through a gate, which extends to the idea of inquiring or intruding.
A horse 馬 sticks its head through a gate 門 to look around and inquire about what's inside.
For チン, imagine the horse's chin resting on the gate as it peers in: chin -> チン.