Jamieson, Fausset and Brown on 2 Kings 11:13

13. Athaliah heard the noise of the guard and of the people--The profound secrecy with which the conspiracy had been conducted rendered the unusual acclamations of the vast assembled crowd the more startling and roused the suspicions of the tyrant.

she came ... into the temple of the Lord--that is, the courts, which she was permitted to enter by Jehoiada's directions (2Ki 11:8) in order that she might be secured.