Doom

When resolving a ranged attack with a weapon that has Doom, increase that weapon's RoF before Target Lock by 1 for each model in the target unit that moved during or after target selection for the command that generated this attack.

Any movement counts, including normal command movement, charge movement, and forced movement from another rule.

Each model counts once. If 3 models in a 5-model target unit moved during the relevant window, increase this weapon's RoF by 3 for that attack.

Doom does not change range, legal target checks, Line of Sight, Field of Fire or facing, Cover, Target Lock, Target Limit, damage, allocation, or removal timing unless another rule explicitly states otherwise.