The huge problem with that, is that Shin is about two feet wide. And unless the circle is more than two feet wide, it literally could not have caved inwards in any angular shape onto his torso. 

Logically, Shin's feet would have been somewhere near the edge of the spire, and would have just been forced upwards by the large spike itself. However, you also included two smaller spikes that were underneath his feet. So unless your column of stone grew another foot and a half wide, and THEN moved inwards onto his body. There is literally no way it could have done how you just described.

Unless Shin were less than a foot thick. Then maybe yeah, it would have worked.