Houston, we have ignition (on the dryer).
AFAIcan reconstruct the scenario, the knob to start it cracked and came off in the PR's hand when she went to dry some clothes. She tried to put it back on, but evidently accidentally knocked the post unit out of the clips that were holding it in place. It took the repairman about 5 minutes to take the panel off and reattach the unit. I now know where the screws are and he "let me watch closely" because he can't tell me how to do it for liability reasons.