Final answer:
The correct CPT code for discharging a patient from Observation like in John's scenario is 99217, as it specifically applies to observation discharge services.
Step-by-step explanation:
To assign the correct CPT code for John being discharged from Observation after his fall from rock climbing, we will use code 99217. This code is used to report a hospital observation discharge service. The codes 99218, 99219, and 99220 are used for initial observation care and do not apply to discharge services.