Wow -- that wouldn't be all that easy to cut off, either, I don't think.
I think if I were dealing with someone wearing this, I'd dump the weight pockets and any weights the diver was wearing, then deflate the BC at least partway, pull the diver's arms up over her head, and try to slide the BC out from under her along the arms. This approach works fairly well with backplates with continuous harnesses, although the width of the shoulder portion of a harness is far less than that BC. But you might try that, the next time you go out to practice.
That is my favorite way to do this Lynne. You just need someone at the controls who can dump it while pulling the bc with one hand and pushing the diver back (hand on divers neck keeping their head out of the water) with the other. Some folks will tuck an arm into one strap like they are chickenwinging (I love that word "chickenwinging" LOL) the diver out this can make things a bit simpler especially if the person is a bit to large for the bcd in the first place.