Morale
These rules cover whether or not NPCs in the game choose to retreat. The Pilots never roll Morale, and it is always the player's choice whether their Pilots retreat or not. NPCs include both those the Pilots are actively fighting as well as any allied NPCs they may have with them. • When an NPC Mech is reduced to 50% or less of its Structure Points, make a Morale check to determine if it stays in the fight. • When a Creature is reduced to 50% or less of its Hit Points, make a Morale check to determine if it stays in the fight. You can also apply this to an entire group rather than individual creatures or Mechs. • When a group of NPCs suffers 50% or more overall deaths or the destruction of 50% or more Mechs, make a Morale check to determine if the entire group stays in the fight.
Source: Salvage Union Workshop Manual, p. 268