"No, I know I considered it, which I told your brother when he apologized. We had agreed it was a last resort, and it sounds like they believed it was at the time." And they may have been right! Istredd told Castiel that he didn't blame him for his impulsive decision while in the middle of the madness. Louis and Inej were also just doing their best at that point. It just meant that Istredd felt it underlined how little he could look away.

The fact that it was Castiel's choice to release the shrine monster may be new information.

"I could argue it was the right choice, it is what led to the escape." So maybe he should have gone crazy sooner. "I don't know, the point is, we were all doing our best. I'm not a hunter or a warrior, I couldn't fight the monsters or get us rats, my helpful abilities were limited." Lucifer knows that Istredd has a thing about feeling useless.