Er... exactly why is somebody who is just "not communicating" a medical emergency needing an ambulance anyway? Bleeding, yes, not breathing, yes, broken limbs, yes, but who would call an ambulance for a perfectly well person who is just staying silent? Psychotherapy, yes, emergency ambulance, no. Why is this person going to be any better off in casualty? I'm sure if they ignored them for a bit and they realised nobody was taking any notice they would just get bored.