In training, it would be best to remove the harness by unbuckling it to see how easy or hard it will be to get the "victim" out of the harness in a rescue class. Instructors never know how that will go. In some classes, it will come right off. In other classes, the harness might not clear a drysuit shoulder dump.
In real life, cutting it will be the path of least resistance.
In real life, cutting it will be the path of least resistance.