If performance is an issue, then we have been under-engineering our platforms. Delivery of ordnance typically doesn't require the extreme edge of the envelope flying. The only thing enhanced by dropping it is reduced parasitic drag, (or in some cases increased drag because of the loss of an aerodynamic store).
In any case, it found its way to earth, perhaps looking for added benefits from a dumb luck hit.
You drop the tanks when needed....before they were destroyed (and "every AA missile" can never be destroyed!) many AA rockets were fired at US planes.
To increase manuevering rates, increase up exit speeds when evading a missile, etc. the drop tanks are the first to go. Bombs too - sometimes. After all, you still have to deliver the weapons, and sometimes that means staying on the drop path while the rocket is inbound.