However, my point is that the Dutch could have unilaterally stepped outside of their own ROEs instead of expecting others to take that decision.
Putting that a bit more delicately, they could have applied their national laws of self defence. There would have been absolutely no legal come-back as national rights to self-defence trump ROEs. The only question would be whether Dutch self-defence laws extended to protecting others.
The way round that problem would have been for the Dutch to have planted themselves firmly amongst the Bosniaks so that it would have been impossible for the Serbs to attack (e.g. by shelling) without provoking a self-defence response from the Dutch. Hindsight is a wonderful thing.