If you damage and opponent's Hull with a [Critical hit], you may immediately discard this card to search the damage Deck for a 'Warp Core Breach' card instead of drawing a random Damage Card. Re-Shuffle the damage Deck when you are done.
What happens if there are no Warp Core Breaches in the damage deck? Due either to having been drawn as face down hits or face up crits - not due to an altered damage deck.