What does 1 Kings 16:10 mean?

Zimri came in, struck Elah down, and killed him. This happened in the twenty-seventh year of Asa’s reign over Judah. Zimri then took the throne. 1 Kings 16:10 - Modern Text Bible

(Zimri assassinates Elah and immediately claims the kingship. The timing is again tied to Asa’s reign, emphasizing the instability in Israel.)