Besides the tourniquit two other items were found in Johnston's pocket
I have read where he did have a tourniquit in his pocket or at least something that could have been used as one..His personal doctor was not close by because he had sent him to tend to wounded Union prisoners in the rear. Dont think anyone would be able to tell if it was friendly fire or enemy fire that struck him. Since he took more than one ball it may have been both. Thus is what happened to many Generals in the war who were more than willing to lead from the front instead of the rear. A big problem for the commanding general trying to keep his key men out of harms way to fight another day..