Logic brick control of camera with mouse, can't lock Y axis

I’m brand new at this so maybe dumb question.
I am porting over a Myst-style game (panoramic panning) and the first action I’m trying to create won’t work right.
When I Sense a Mouse Movement and try to Actuate MouseLook of the camera, the (local) Z axis of the camera changes no matter how I manipulate the settings, the image cumulatively yaws. I’m somewhat familiar with the complexities of stacking rotations but none of the axis type settings of the camera will work. Is this possible or will have to resort to python (already!)?

I had to experiment at the python console to work this out; makes sense now:
use X axis, mapped to Z axis, NOT local.
use Y axis, mapped to X axis, IS local.
Resets don’t seem to matter.
Geeze, glad I didn’t have to use python for such a simple task!