A quiet torpedo launch still risks an active-sonar counterattack

Would a quiet, delayed-activation torpedo launch keep the attacking submarine safe?

Not necessarily; the escort can switch to active sonar and launch a counter-torpedo along the bearing of the attack.

Wire guidance and delayed activation improve the attacker's concealment because the weapon can travel away from the firing boat before going active. They do not remove the defender's options once a torpedo is detected. An escort can immediately switch to active sonar, search down the incoming line of bearing, and launch a rapid counter-shot. The attack therefore risks becoming a lethal localization contest in which the submarine's first weapon also gives the screen a reason to reveal and pursue it.