In a Cessna 182 (rental) I once had a throttle mixture knob and cable come right out. Luckily it happened during my run up before taking off. Taxied right back to the hanger and changed planes….. mechanical things even with maintenance can still fail…
Great that it happened on the ground! I once had the oil cooler go kapoosh during a ground runup while in for an annual. The week before we had been at about 10,000 feet next to Denali. Nothing around there but jagged airplane eating teeth.