Pleas read up on the Drummer. It is not what you obviously think it is.
There are no individual pattern as in MIDI Events in a MIDI Region. The Drummer is a Drum Pattern Generator. You adjust the various play parameters (descriptions on how and what to play) in the Drummer Editor, and it creates MIDI Events based on that on the fly sends it to the Drum Kit Designer (the Software Instrument) that "plays" the sound.
The Drummer Regions are just visualization of the generated pattern.
Drag a pattern over to an Instrument Track (preferably loaded with the same Drum Kit Designer assignment) and you can see the actual MIDI Events in a Region.