At what point during the transaction should the pay at the door activate? I would have though it would be before they are required to add their credit card details.
If you select Pay Later for the payment option, then credit card details will never be shown. In your config, make sure you have "Pay Later" selected as one of your options. It will show along with the credit card option as a separate page instead of going directly to credit card payment. Also be aware that this can be set per event... but the payment settings seem in the event setup will only apply INSTEAD OF the global payment options if that tab is set to "Unique" instead of the default "Global".