I'm sad to hear that. I would not want a victim to go with a request for help to WMF, local functionaries, an arbitration committee, or anyone else, and have the situation end up worse rather than better. I don't know what to recommend. Perhaps you could ask the stewards what they think.
I am also sad to hear about the difficulties regarding the situation in which you think that someone was at risk of self-harm. I think that the situation you described is probably appropriate for review by the management of WMF Trust and Safety so that they can take a second look. I encourage you to contact them.
I am finding this conversation to be rather depressing, but I am glad that we are having it, because this is one way of developing solutions.
Pine