Just analyzing the man's statements for basic "tells" of non-candor and non-forthrightness, like they do in law enforcement:

1) "What I can tell you is..." - That's a distancing, qualifying phrase - we might call it an abstraction layer. It's like there's an AnswerTheQuestion() method that instead of just returning an answer, has to first call the GetAThingToTellThem() method. Hmm interesting. Great separation of concerns if you're a computer program, but totally unnecessary if you're being concise and direct.

2) "What I can tell you is that I did not cut." - It's a non-denial denial. He doesn't actually say he didn't cut. He says he can tell you that he didn't cut. (OK go ahead and tell me then, whenever you're ready.) He can also tell me that he's a purple elephant that farts rainbows.

3) "...I did not cut" - Resorting to a formality by eschewing the contraction - using "did not" vs. "didn't." And I wouldn't make the usual allowance for Latin heritage, because he's a doctor and has been in the US for a long time, plus he uses contractions freely elsewhere (didn't, I've).

4) After starting two sentences with "I've", notice in the last sentence (the second it comes time for another direct denial), it goes back to formal language: "I have."

5) "I didn't know this was against the rules..." Getting defensive, trying to portray himself as a victim being persecuted unjustly (totally outside the normal purview of the usual rules which he thought he knew) and therefore deserving of sympathy. Also subtly attacking the interviewer for asking the question. Aggression is a big tell.

6) Overall does it seem to be just impartially reporting/presenting information or does it seem to be making a case or argument by "dressing up" the facts to favor himself? Notice the overall wordiness of the thing and the volunteering of superfluous information. I do this for fun. I don't hydrate properly (WTF does that mean, you tryin to say you drank too much water dawg?)

None of these on their own would be inherently suspicious, and might have other explanations, but occurring all together like this, they're a billboard telling you "Take a closer look."

Edit: Reply comments are starting to object along the lines that this doesn't prove anything. That is correct. The goal isn't to prove guilt; only evidence proves guilt. The goal is only to direct the course of the investigation. You're only looking for "warmer or colder." Keep going this direction or look somewhere else? That's why I conclude with "Take a closer look" and not "Please convict this person of a crime immediately." It's akin to a polygraph reading - fairly unscientific, generally inadmissible, but valuable in deciding what to do next in the investigation.