Jonandek made a video, I’ll link it here: www.elitefourum.com/t/how-i-crack-a-psa-case/28618/1
I crack it similarly. What I can say is that there’s no full proof method, there just isn’t when it comes to this sort of thing. However, if you do it correctly, the chances are minuscule that something goes wrong. Best advice I have is to take it slow and make sure you crack the corners well. It should break apart pretty easily from there.