"Because you retreated? Sometimes that's the best option." Jack learned that from them too. The Winchesters are not good at running though, he's well aware. They would rather stand and fight and so would he, but Jack has learned to pick his fights better. He had to do that when preparing to kill God. Jack would have done anything to get Castiel out of the fight, even tossed him telekinetically outside. Retreated is a nice way to phrase ran away.

"It wasn't fine, it was taunting me. I was being respectful and just looking around, but then it trapped me there." Jack doesn't like being trapped. The gate dropping behind him was an instant lead to twitchiness. Still, he tried to play nice, but he could feel something was wrong.

"You didn't feel what I did. It was threatening me, I could feel it closing in around me." So Jack attacked first because he felt like the temple was going to hurt him. He frowns at Castiel, surprised that he's feeling ... defensive. The temple was gaslighting him.