Wouldn't the bugler be back with the general commanding? No need for defensive weapons other than a sidearm.
Did everyone become familiar with the calls? Maybe they should have practices along with the drills.
Bugle calls
There was a sergeant in charge of us "number fours," and he was as cool as any fellow I ever saw. The sergeant was a nice man, but he was no musician. He was an Irishman, also, and when any bugle-call sounded he had to ask some one what it was. There was a great deal of uncertainty about bugle-calls, I noticed, among officers as well as men.
Of course it could not be expected that every man in a cavalry regiment would be a music teacher, and the calls sounded so much alike to the uncultivated ear, that it was no wonder that everybody got the calls mixed. In camp we got so we could tell "assembly," and 'surgeon's call," and "tattoo," and quite a number of others, but the calls of battle were Greek to us. The bugle sounded down in the woods, and the sergeant turned to me and asked, "Fhat the divil is that I dunno?" I was satisfied it was "To horse," but when I saw our fellows come rushing back towards the horses it looked as though the order was to fall back, and I suggested as much to the sergeant.
The sergeant ordered retreat, and Mr. Peck and his horses took off at great speed, even though the approaching men were calling for them to stop. Of course, he gets into trouble for this, which he relates at length humorously.
How Private Geo. W. Peck Put Down the Rebellion, or the Funny Experiences of a Raw Recruit
George W. Peck, 1890, 4 WI I/C