I'll bite. Beside the external/internal, are there other features that make it 'entirely different'?
Really? I have to explain how different they are? How long a list do you want me to make?
External: No clue about the auditor by client
Internal: Auditor is well known by org.
External: No clue about the business (possibly only general terms)
Internal: Very familiar
External: No time to prepare, study and understand QMS
Internal: All the time necessary
External: No clue about personalities, management style, culture etc
Internal: Knows all those things
External: No clue of contemporary quality issues
Internal: Knows the above
External: No clue about relationships with customers and suppliers
Internal: Knows the above
External: One audit a year
Internal As many as necessary to be effective
External: No clue where skeletons are buried
Internal: Has shovel, knows locations of plots and who's buried there
Should I continue?