Seriously, these threads are getting out of hand. Now we got people wanting to know if its okay to shoot someone for walking across the parking lot. It used to be that these types of threads involved wanting to know if it was okay to draw down. Now we want to shoot someone because a dog is barking, some dude wanted to buy my GF a donut, the mail was late today, and so forth. These are the type of conversations that when carried out in public fuel the fire for the antis. But to answer the OP and not remain off topic any longer
NO YOU CANNOT SHOOT SOMEONE SIMPLY BECAUSE THEY ARE WALKING IN YOUR DIRECTION AND YOU ARE SCARED BECAUSE HE'S BIGGER THAN YOU ARE.