You are in uncharted territory claiming to have broken off a DV Holder inside the IP. Can't imagine how much torque it took to do that or what happened internally. Spec torque is 35NM or 26 ft lbs. Is not much, just enough to seat the holder on the crush washer and to compress the oring.
If your pocket book can handle the hit of a used/rebuilt IP (~$1500-2500) then have at. Again, you are in uncharted territory so not being able to see pics and understand exactly whats happened is going to limit the amount of useful input you receive. You obviously cant drill because you cant risk contaminants and you can't beat on it or heat it with a torch cause you might warp something or melt other seals you can't get to. Probably leaves some sort of easy-out. Might want to talk to a local guy who extracts broken head bolts for ideas...?
If your pocket book can't take the hit of a used or rebuilt IP, the Bocsh tech and a flow bench will prob run $1k, if it turns out in fact to be a recoverable mistake.
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Ref the attached detail:
http://homepage.ntlworld.com/tom.jeffs4/car%20stuff/merc%20tech/diesel%20delivery%20reseal-1-1.pdf
You snapped #7 off inside the IP, right?
Did you pull #7G up out of the hole before you did that?