Hive Mind triggers, causing each opponent to copy Doomsday.
Resolve an opponent's Doomsday, causing them to exile their library and not search for any cards due to Ashiok, and lose half their life total, rounded up.
Repeat step 4 for each remaining opponent.
Resolve your Doomsday, searching your library and/or graveyard for five cards, exiling the rest of your library and graveyard, and putting the five chosen cards on top of your library in any order, and losing half your life total, rounded up.