This actually seems fine to me. It seems like the player’s specific intent was to push boundaries by taking risky actions, in an attempt to judge if the GM will actually follow through on consequences. It’s a way to establish stakes.
Long, long ago I had decided to be a no-kill DM. I had a player who kept pushing it so after a while I gave up and killed off his character. When I was out of the room he admitted he was wondering what he could get away with and was actually happy I killed their character. Pretty foreign concept to me but now I will never guarantee survival. So plot armor? Sure. Invincible plot armor? Nope.
Oh, and the guy left the game not too long after for a variety of reasons. He had some odd ideas about what he wanted out of the game that simply didn't mesh well with the rest of the players and a few other issues.


