This same shyt happened to my brother while we were running pick up outside on concrete, twice. The first time he could barely breathe it was so painful. He came back to early after rehab and the same shyt happened again, but he was calm as hell and just talking like nothing happened that time. He said the 2nd time didn't hurt at all, but he knew what happened before even seeing it. With Baron having so many knee injuries it was probably very similar. His shyt probably just collapsed like some loose legos after pressure is applied.