Other mistake: After the stagecoach crashes and Mary discovers that neither Marge nor Adam can move, she tells Adam that she's going to leave the canteen for him and Marge. Neither one can move. Neither one is going to get the canteen to the other.
He Loves Me, He Loves Me Not (2) - S6-E26
Other mistake: Charles has just brought Adam a letter to the site of the blind school rebuild. When Adam is told that his father died, he and Mary walk away from Charles. The terrain was very uneven. Being blind they realistically wouldn't be able to navigate it without stumbling.
