My PI is also a clinician in my current field of interest. I've shadowed him a couple times and would be interested in setting up a long-term shadowing experience with him. However, from the point of view of LORs and apps in general (MSTP), would it raise red flags if my research and shadowing letters are from the same person? (e.g., make me look antisocial or not into networking?) Is it advisable that I choose someone else to shadow? I'm interested in a fairly narrow, specific specialty (same specialty I do bench research in), so would even shadowing anyone in this field look weird, or at least limited?