Attack Progression: Seevor v Qi'ra

Seevor vs Qira: If a ship with Qira is overlapping an obstacle they have locked and they declare Seevor as the target, would Seevor ability, jamming off the lock, prevent the attack from happening?

No, Seevor's ability cannot prevent the attack because the ability triggers when the attack as already started. Seevor's triggers before rolling dice: once the lock is gone, the obstacle can obstruct the attack.

Seevor's ability can prevent the ship equipping Qira from performing a bonus attack after the first one.