Let's go back to the beginning of the season; specifically the Heritage episode:
Sarah asked Johnny "How could you not see this coming?" and "Why was my husband here (Faith Heritage Chapel)?" These were good questions to ask at the time. However, there are some questions that the character of Sarah has yet to ask...
I wonder when the initial shock wore off, why the character of Sarah has not asked herself, or anyone else for this manner other pertinent questions such as: a) "Who was the other guy (Malcolm Janus) who died in the Chapel with my husband?";
"Was my husband meeting this man?"; c) "Is this individual (Janus) part of Walt's investigations and/or allegations against him?"; and d) "Who does Malcolm Janus associate with (Greg Stillson) and how does he know Walt?"
