heres a video of breeching with det cord... we did ours at this same range, just some other time. Only diff is here they have people stand far far back... for us, our instructors had us stand up against the cinderblock wall 1-2 feet from the charge. I still have the blasting cap shrapnel in my legs and hand to prove it.
http://www.youtube.com/watch?v=YuWiSSVEPrU