12.2.3 - Tied Initiative

When you reach an initiative step where both you and your opponents' models would act, both forces models resolve their attacks sequence (see 12.2) at the same time. This is done first, by the active player who resolves their attack sequence. Then the opponent can resolve theirs.

However, any models slain in the same initiative step in which they are also making their attack sequence still get to fight and resolve their attacks before they are removed from play from any wound allocation in that Initiative step.