Aquila, unlike the crowd, is skeptical towards the elixir and doesn't agree that Marston has performed any miracle, and challenges John to shoot his hat out of the air. When John does so, Aquila becomes angry and challenges John to a fistfight. When Aquila loses the bout, he draws his gun, scaring the crowd, but is promptly disarmed by John.
John's ability to overcome any challenge Aquila throws at him causes the crowd to buy and drink large quantities of West Dickens' elixir. Aquila is then seen joining the crowd near the table of elixirs saying, "No harm in trying one bottle, I suppose.", showing that he has also been convinced by John.
You can fool these people, but you ain't foolin' me!
Hey! Hey! What? You think you can just put a hole in a man's hat and just walk away? Do ya?!