The simple answer is: just go around!
Once you are in the situation where you are looking at a full scale deviation in the expanded mode, you are outside the safe flightpath.
Even if you would have had the raw data display, you would still be in the same place. In IMC there is only one option: go around!
Flying in the expanded mode also gives you the advantage of the deviation warning.
Trying to recover from a position that far from the correct one, in IMC is not a good decision. Just take your losses and try again fresh.