Each Firethrower operates as a separate unit. If a Firethrower is targeted by missile attacks and is within 3" of a friendly Infantry unit, it may use "Look Out, Sir!" as if it was a character.
Source: Warhammer Armies Project: Unofficial 9th Edition (v2.2)
Each Firethrower operates as a separate unit. If a Firethrower is targeted by missile attacks and is within 3" of a friendly Infantry unit, it may use "Look Out, Sir!" as if it was a character.