You also assume. Why wouldn’t they testify if they felt that the doctor did nothing wrong? Or simply to tell what they observed, right or wrong? Knowing what happened, they would, I would think, be duty-bound to testify to the facts. Once the grand jury had the facts, then they would be duty bound to act on them. Looks to me like they think they did, or wouldn't they have had the doctor charged?
They didn't feel this at all.