I snapped a cable in my RH Ultegra 6700 10 speed shifter. The cable head was frayed completely and I could not shift to the "neutral" position to remove it. I read a good description about drilling an access hole in this thread (including a few comments wishing Shimano would incorporate into future designs). Now I can report that they have incorporated something like an access port for snapped cables - a "second chance" to get it out.
I tried to rotate the cable barrel with all sorts of tools and grab the frayed ends with tweezers and eventually decided to completely pull back the rubber hood to see where to drill the hole. Then I noticed that there was already a hole in the appropriate place. I downshifted with the big lever until the lead cable-head came into view (easy in that direction). Moreover, the black plastic cover circled in the picture simply unhooks and slides forward providing ample access for tweezers. It is not even necessary to untape the bar.
I whipped out the old cable and stray bits of wire, threaded a new cable through the correct access hole at base of shifter, re-indexed and now it's fine.
With the later models of Shimano shifter (6700) this might be commonplace and obvious to everyone else, but it wasn't to me, just searching the internet. I got in a right sweaty mess!
I hope the picture helps someone:
