RE: Texas GS Law:
"stop and render aid" does not mean that you have to physically stop and start compressions on someone or anything else. When I took my Red Cross class, this was explained to us. Using your cell phone to call 911 is "stopping and rendering aid." That is all that you have to do.
RE: OP, I think not, outside of tossing the BG a shirt and explaining how to apply pressure. I may be so inclined as to offer up supplies out of my small pocket FAK if it will help. All of the reasons fornot acting that I could mention have been brought up so far. I do not know if the BG is 'faking', otherwise armed, accompanied by friends, infected, etc. I am not going to compromise my safety. At work, however, it may be a different story. If somebody is on my post (i work security) and deadly force is necessitated, I will do my best to 'secure' the area, call for back-up and EMS, then do what I can, even if it is to simply toss the BG some Quik-Clot and instruct from a distance while keeping my weapon at low ready...