When the fire breaks out in Thunderclan camp why did Ashfur leave Lionblaze Jayfeather and Hollyleaf there?

Ashfur is angry at Squirrelflight because she decided to love Brambleclaw instead of him, even after they became romanticly envolved. He decides leaving and trapping Squirrelflight's kits (i. e. Lionblaze, Jayfeather, and Hollyleaf) is a good way to get revenge at her. That's why Ashfur does so.