Matthew 16:23 But he turned, and said unto Peter, Get thee behind me, Satan: thou art an offence unto me: for thou savourest not the things that be of God, but those that be of men.
Peter didn’t want him to be crucified. Different situation. He was just expressing his dismay at the thought of a good friend being put to death.
How would you feel if your best friend said that he must go somewhere and then be put to death? Wouldn’t you say that he/she was nonsensical too?