I think this is the best theory this far.
I loved this quiet ep. I liked seeing how people dealt with various forms of anger. How the assistant tried to appease Renata, how Nathan got frustrated with Ed, how Bonnie spoke with her father, how the boys beat the crap out of that bully, how Celeste pulled back her anger when Max (?) called her a bitch.
BTW, I thought her response in that moment was great. Controlled anger. For the parents on this thread, has your kid ever called you a nasty name and how do you respond? I honestly don't think I would respond well.
The other thing I loved was seeing Nathan working on his marriage, mostly off screen. He is running, got a treadmill, is being supportive at the hospital. This is in contrast to Madeleine is trying but maybe won't take up golf.
And then Renata's husband who does listen to her while she rants. I don't think he is a potential suicide like someone suggested. I think he is made of tougher stuff. Renata picked him for a reason.