Ouch, Jorge! I hope you had a nice drink after that one.
I have removed the darkslide without closing the shutter blades a few times on 4x5 and a few times on 8x10.
I had a grafmatic jam on me during a workshop a couple of years ago and I lost 6 sheets of IR film because it was really jammed. After the same workshop, I was shooting some 4x5 halfway up a mountain and heard a pop when I pulled the darkslide. The film had popped out of one side of the holder and nothing I did would save it. I just pulled it out. Someone else had loaded this particular holder (note to self, always do it yourself).