Tom, you raise a good point. One needs to get the test, receive the results, work through the portal for your destination, get there, and still have enough time remaining to get through the portal and arrive at the next destination.

More than one person has nearly been on their way to the airport before getting BVI clearance. In fact we have a neighbor who got stuck in San Juan when the BVI messed up her clearance. In Mal's scenario, I would want back-up plans for testing on St. Thomas.