I knew this wasn't going to be a walk in the park. So many systems were identified that the overwatch feature needed to interrupt and then resume in a particular order to function as intended. The system is still far from being perfect and some unwanted side effects still need to be fixed, but alas, its main functionality is done.
The video below shows the red team setting up their overwatch-related field of views and then the blue team stepping into those areas triggering opportunity shots.
Stay safe!