Tom,

It's pretty weak to suggest that sarcasm would be rejected on the grounds that we don't see it as part of his "regular" personality. Firstly, Peter doesn't write near as much as Paul does, just these two books (that we know of, I think). Yet in one of two of them we see this sarcastic remark. Paul does not use sarcasm in half of his books as Peter does. If we go by odds, we would see Peter doing it far more often than Paul already.

Secondly, Peter was a vivacious personality anyway and from any regular observation of humankind just about anybody is prone to a sarcastic remark now and then, including hotter headed types. I use sarcasm extremely rarely, but when I do it would be a mistake for the one to whom I'm being sarcastic to presume they have figured out something "regular" about my personality.

It doesn't take any deep psychological "trait to warrant the use of sarcasm....a bit of wit and an opportunity is all.

Barry