Unfortunately, when this episode started, I paid too much attention to the story.
The outlaws rob banks, and their leader does his research. The experienced crew has taken their positions to rob the bank in Dodge City. Along the way to the bank, the mastermind taunted their victim, Albert, with crucial information.
As viewers, we're privy to the following. Albert leaves his "apartment" at 8:30 every morning and "opens the bank a minute later," wherein Albert has "opened the safe for 15 years."
Everything goes according to plan; and in less than six minutes into this episode, the outlaws - in their calm, deliberate way - have the safe opened and Albert surrounded, including a lookout at the door.
An elderly woman knocked on the door and called for Albert because she knew he was in there.
Customers and outlaws alike knew Albert opened the bank at 8:31 every morning.
The outlaws looked at each other in shock, and their facial expressions told the viewers they were not prepared for a customer coming to the bank after it opened. The lookout was a dud.
Albert took advantage of their petrified state, after which the outlaws escaped emptyhanded through the back door, where their horses were tied.
I spent the remainder of the episode realizing if the outlaws had spent five seconds grabbing the loot before running when the customer knocked, then the rest of the story would not have been possible; and noticing nothing else petrified these outlaws. Not visits by the U. S. marshal. Not more customers. Not the guns that were pointed at them, or the shots fired.
The story depended on these outlaws acting uncharacteristically during one "unforeseen" moment - when a customer knocked on the door while the bank was open.