Why would Sassy want to go back?

[edited for clarity] Either Cherry’s own storyline is now moving along concurrently with Mark’s (as in, things are happening that we did not observe), or Cherry is just making a rash assumption before the results are in. When we left off, Doc Davis had only proved that Honest Ernest’s lawn treatment chemical cleans dirty coins faster than a carbonated drink could. That doesn’t exactly prove it is the source of the pet rash.

Still, if Cherry wants to find the possibly offending lawn, it seems to me it would be more productive to walk through neighborhoods with lawns.