Putting your finger in the way is NOT a good idea!
I was decapping some .44-40s yesterday, using my Lee turret press. I still don't know how it happened, but my left index finger ended up on top of the case, resulting in the obvious - the decapping pin went into my finger at the first joint!! I'm not sure how far in it went (and I don't want to know) but I think it's going to take a while to heal.
Dumb! Dumb! Dumb!