That was me keeping you alive. Perhaps you didn't notice, but Zelman had the upper-hand in nearly everything you threw at him. [No, nuh-uh. Neither of you are getting a chance to speak.]
[Takes a step forward in the already nonexistent personal space.] What was I doing the entire time, Sam? [Shoots a glare to the other Winchester.] Dean? [But before they can answer, Cas starts off again.] I was keeping him from harming either of you. We went in thinking that we were prepared, but we weren't. He's stronger than we had imagined and he could have easily killed the both of you if I hadn't been present. Especially you, Sam. [Turns his attention back to the youngest.] Barely into the attack and you lost yourself.