When Festus leaves the Longbranch after Doc's letter is read, he is seen in the street by Doc's office and it's obvious that Doc's window is open with the curtain blowing in the wind. An camera angle change shows the window and it is closed. Back to Festus, and it is open.
The Dr. Chapman returns to his office to find Festus had fallen asleep in the chair while keeping an eye on Newly. The doctor lights a lantern and says that night is just falling. Delirious Newly wakes up and runs outside with Festus and the doctor chasing him, and now it is fully dark.
Everyone outside is bundled up against the very cold March weather, but the Longbranch's outer doors are always open, and the saloon girls sit near the swinging doors wearing sleeveless dresses with their shoulders bared. The men have their coats on.
Newly O'Brien asks Festus to hand him a dipper of "black powder." But in the 1870s, when Gunsmoke is set, smokeless rifle powder had not yet been invented (1884), so black powder was just called "powder."