The speaker describes a getaway that sounds like a crime scene. Something is tied up and thrown into a pickup truck, and the speaker speeds off into the night. The poem never says what was bundled up, and it never says exactly what happened, which keeps us uneasy and leaning in.
Then the night seems to answer. The speaker imagines it roaring back with "oblique animal rage," bending moonlight into words and words into near-miss collisions. The speaker admits this may only be a thought ("or so I thought"), so it's hard to tell whether the anger is real or a product of a guilty mind. In the last stanza the speaker offers an odd, almost casual explanation: the night is mad because a bullet was left in a stranger's shoulder. The tone is tense and dreamlike, with a strange calm sitting on top of the violence. The speaker seems haunted, as if the act can't be outrun, however fast the truck goes.