Typically, market forces get you to this Goldilocks rate. Yet there are circumstances where rapid capital inflows or outflows can move the rate to a level that is unlikely to be supported by fundamentals.
So time is absolutely of the essence in regaining control of a hectic situation: acting expeditiously is a must. Third, whatever the nature of the turbulences, which would hit the global financial system, the multiplicity of entities and parties involved, whether private of public makes it necessary to agree as much as possible ex-ante on the appropriate ways for handling the situation.