When a spell resolves , you follow the instructions written.
So if you choose the second and the third/fourth mode of Austere Command , Bloodchief ascension will be destroyed before all creatures will be destroyed = Bloodchief's second ability will not trigger.
EDIT , Even if Bloodchief is destroyed at the same time with other creatures (Planar cleansing perhaps), its second ability will not trigger too. Because the second ability isn't Leave the field triggered ability.
From Gatherer.com Ruling of Bloodchief ascension itself.
Bloodchief Ascension's second ability doesn't behave like a leaves-the-battlefield triggered ability, since the card put into an opponent's graveyard may come from anywhere. If a Bloodchief Ascension with three quest counters on it and a permanent an opponent owns are destroyed at the same time, for example, the game will not "look back in time" at the game state, and Bloodchief Ascension's second ability won't trigger.
4 player game.
Opponent has an active Ascension
I have 3 creatures.
Other players have 4 creatures each.
I use the command to destroy all creatures and enchantments.
Do the other players and myself lose life when all the creatures go the graveyard and Ascension as it goes to the graveyard?
http://www.youtube.com/watch?v=SY8h2vp5Xis
So if you choose the second and the third/fourth mode of Austere Command , Bloodchief ascension will be destroyed before all creatures will be destroyed = Bloodchief's second ability will not trigger.
EDIT , Even if Bloodchief is destroyed at the same time with other creatures (Planar cleansing perhaps), its second ability will not trigger too. Because the second ability isn't Leave the field triggered ability.
From Gatherer.com Ruling of Bloodchief ascension itself.
Bloodchief Ascension's second ability doesn't behave like a leaves-the-battlefield triggered ability, since the card put into an opponent's graveyard may come from anywhere. If a Bloodchief Ascension with three quest counters on it and a permanent an opponent owns are destroyed at the same time, for example, the game will not "look back in time" at the game state, and Bloodchief Ascension's second ability won't trigger.
Obviously , English is not my first Language (sorry about that ).