Bahasa Jepangnya “saat diperlukan”

saat diperlukan; jika terjadi keadaan darurat

(when) the time of need arises; should an emergency occur

saat genting; saat diperlukan; dalam keadaan darurat

at the critical moment; when the time comes; when it's most important; when necessary

langsung saat diperlukan; secara langsung

on-the-fly; on the fly