What do you mean...theoretically? – An explosive nova is triggered when shields and/or health are depleted.
Usage & Description
The Deadly Bloom is particularly ideal for Krieg with a melee build. The explosive damage type can do a number on shielded foes, allowing for easier burn damage. It's also an easy recovery from a failed Buzz Axe Rampage, as he's nearly always within range.
This shield is also useful for any character to assist in getting second winds as the secondary explosion can quickly revive the character, even if an enemy is behind them. Using it to this effect is easiest when either focusing on close combat or to protect against common melee enemies that may ambush unexpectedly.
The Deadly Bloom's special effect is always triggered when the wielder enters Fight For Your Life mode--regardless of whether the shield has recharged since the last nova.
While it is displayed in the inventory as a purple-rarity item, the Deadly Bloom is internally classified as a legendary and is part of the general legendary loot pool. Because of this, the shield has a small chance to be found from any suitable loot source, including from chests and other containers as well as from defeated enemies.