There is a specific sequence for loosening the cam towers, the upper half of the bearings retaining the cam. The sequence accounts for the pressure on the cam by the valves that are open when the engine is at #1 TDC. Randomly removing cam towers can cause the cam to bend. I suppose in an unsuitable situation such as if the crankshaft is stuck I would release each cam tower bolt a quarter turn at a time until all are loose. That should minimize the risk of bending the cam.

Sixto
87 300D