In the above image, the blue highlighted part moves up, the flipper contacts the shaft on the yellow part, and the flipper moves out of the way to accept the shaft on the yellow part.  In the position shown, physical dynamics stops and can't find a solution.  Can anyone tell from the picture if it should stop there, has it just been a long week for me, or should physical dynamics be able to find the solution I want - the flipper keeps moving out of the way for the shaft to come through?