I'd like to point out that just because it is expected that folks are going to try to come and try out a product (and potentially damage it) does not justify it.
OP entering a funky command is not unexpected. But then purposely antagonizing the sales rep was a d*ck move in my book. If OP had just shown the guy "Hey here's what I did and what it does" that would be perfectly fine (important distinction, OP knew more than the sales guy compared to your case). But if the sales person was legitimately panicking that's not very polite, to put it mildly.
OP entering a funky command is not unexpected. But then purposely antagonizing the sales rep was a d*ck move in my book. If OP had just shown the guy "Hey here's what I did and what it does" that would be perfectly fine (important distinction, OP knew more than the sales guy compared to your case). But if the sales person was legitimately panicking that's not very polite, to put it mildly.