Where do we start? With the obvious alcohol factor - all day drinking sessions are a recipe for disaster, no matter who is involved. All of them are in positions of responsibility, and are paid as such, so at least one of them should have realised that it was going South at some point. I would have expected better of the officer, but it can't all be laid at her door - the killick must accept her share of the blame for being involved in the situation. The only one that seems to be outside the punishment envelope is the PO, but legally that cannot stay that way - failing to exercise proper control should be a laid charge. In fact, the PO should take a fair whack of the responsibility. The obvious solution would have been to recommend that the officer gets in a taxi and returns to the nearest establishment, and the killick is accompanied in a taxi (a different one) to the same establishment - the whole situation should then have been handed across to the OOD. If they were not near an establishment (one that wasn't serving Aftershock, obviously), then the PO should have gripped them both and explained that this was not conduct becoming, and they should sort it out.
The charge only appears to be fighting, not drunkeness, and if there is CCTV then they are both stuffed, as it were.
The benefit of hindsight is a wonderful thing, of course!