In a previous episode, Huell had insisted on frisking Jesse before allowing him into Saul's office. It was during this frisk that the ricin cigarette disappeared.
This is the connection Jesse made while waiting for the pickup van and discovering that his dope was gone.
I missed that- so did walt actually poison that girls daughter? wow... i must have missed more than I thought
I know he made a replacement cigarette and went through the whole charade of searching the house for hours, only to pretend to find it in the vacuuming robot
And if jesse put 2 and 2 together and realized Walt poisoned the kid, that’s gonna be bad ....
it will certainly lead to a showdown
But Brock wasn’t poisoned by the ricin, he was poisoned by the Morning Glory plant in Walt’s back yard, so why would Jesse think it was the ricin cigarette?
Ed