Whichever these demons were, they were serious. And deadly. One only had to look at the devastation around them to know that. But the fact they'd kicked Ruby made Castiel momentarily furious, his eyes darkening dangerously. As she commented about leaving he looked at her, moving his hand to touch her arm briefly, looking her in the eyes even as she tried to avoid his, a look saying a whole lot of words. Be careful. Don't get hurt. Go straight home. Please. He knew she wanted him with her, but he still had duties to do here, and he knew others would come. Other Winchesters, possibly the Hyperion. Not to mention Claire and Dean with the knife. It would be safer for her to go straight back to the apartment so he could join her later.
After several seconds he turned to look at Claire sternly.
"You," he stressed the word heavily. "Also need to sit down. Or I will glue your ass to the floor." He stepped away, looking at the dead and dying demons. It would break so many rules and use a lot of power from himself, power that would leave him vulnerable, not to mention potentially get him in a lot of trouble.
But, if he didn't, Claire would no doubt slice open arteries again, which would distress Dean and protecting Dean and his loved ones was his sacred duty.
"I can deal with them."
He was sure it was Winchester influence that made him so open to bending the rules.