Mayo ~~ Senior officers are appointed in recognition of their ability to decide on appropriate action, and hence to issue appropriate orders, in accordance with their judgment of a situation. In the circumstances you postulate, a CO would decide as to the best course of action, but would be unlikely to order his men to intervene as they could then possibly inhibit, rather than assist, the work of the appropriate authorities [in this case the Fire Brigade] -- but this would be a matter for his decision according to the circumstances prevailing. All would depend on the Colonel's assessment. In the case with which this thread is concerned, I repeat, an order from a CO to his men to intervene would be ultra vires, and I do not think any CO would assess it otherwise.

~M~