Hopefully he was just having a bad day. I dont see anything in your correspondence that would be offensive.
You asked him if an earlier meeting was possible. It was not an ultimatum.
You let him know you were running 10 minutes early, and the way he responded to that was a bit snarky, for whatever reason. You had no idea he was eating. Many people would have just showed up at his door at 4:20.
You also assured him you could wait until the appointed time.
Perhaps he is stressed out because of the current situation, and I dont want to judge him. But you did nothing wrong in my opinion. If 4:30 or 4:20 was potentially going to be a problem, he should have told you that the original time was preferred when you first asked about an earlier meeting.
I expect he was trying to please you by agreeing to an earlier time. But that kindness was sort of erased by his later reactions. You wouldnt have known or anticipated that, and I have no doubt you would have kept the 5pm time had you known what would have happened. But none of us are mind readers... at least I am not.
I hope he contacts you, and that you can work it out. Or reach out to him in a while. Both of you are likely very kind people who got off-track via electronic communication, which is never as clear as face-to-face.
Just my two cents...