2004 Cadillac SRX cruise control problems

My 2004 cad. Srx showed a left rear flat tire. I pulled the vehicle to a level, asphalted, scenic overlook area, 23 miles from page, az. I could not get the shifter from drive into park gear, nor would the key turn or release from the ignition. I got out to check and change tire, spare would not release, either. I called on-star, gave emergency details, to first advisor, then advance diagnostics.

When activating the resume switch to a set speed of 65MPH, the switch sticks in the resume/acceleration position, resulting in the vehicle accelerating past the set speed, too speeds greater 85 MPH, prior to disengaging the cruise control. This has occurred three different times over the past five or six years. The condition was intentionally induced on one occasion.