He could only fervently appeal to the better natures of the terrorists. He was unarmed. Like the heroic teacher who died in the closet while trying to cover her students, wouldn’t it be even more heroic to die (or survive) while killing or trying to kill as many terrorists as possible, preferably with your own concealed weapon?
It is not possible for it to be more heroic. If you're lucky, or a good shot, it might be more effective.
"Greater love hath no man, than he who gives his life for his friends."