In the car, Brennan says Moses wandered in the desert for 40 days. The Bible says it was 40 years. Perhaps she's confusing it with the story of Noah and the flood, in which it rained for 40 days and 40 nights.
The outhouse blows up because the trucker uses his lighter inside it. MythBusters already covered this - it wouldn't happen. Even in a modern, plastic outhouse, the gases can't concentrate enough to be explosive. It certainly couldn't happen in a decrepit wood outhouse that clearly isn't sealed well.
The tetrahydrozoline hydrochloride eye drops (OTC remedy for bloodshot eyes) given in a drink would not cause diarrhea as the drug is an alpha agonist. More likely the drug would cause nausea, vomiting and possibly constipation. The whole concept is a debunked urban myth that any decent scientist would have researched the facts behind the myth before basing a story arc on it.