You cannot not post spoilers because this forum doesn't allow you to post spoiler tags. Really stupid, anyway. Only thing I can think off is to post "spoiler below" in big bold letters like i will do now
Sentinel, do not read this mate, sorry. It's huge.
@ Steady Eddy
No, all of that made sense (you need to re-watch Gus's history with the cartel) but one thing which did not make sense was HOW did Walt find a way to poison Brock? How did he give it to him and it's weird Brock didn't recognise Walt.