"Finally, let's take the situation one step further. Virginia's application of justifiable homicide is also not in the code, but has been defined by the coursts. It requires you to retreat to the fullest extent possible
, and to be innocent of any escalation in the event. So lets say you show the piece, and things escalate, and you end up shooting a badguy."
This part is not true as I understand it since Virginia does not have a duty to retreat law. Simply put, this means if you havea legal right to be where you are and are not party to the threat in any way (initialization, precipitation, escalation), youwear the vail of innocense and do not have to retreat.
However, prudence would dictate that retreat is better when available in order to either keep a situation from becoming a real threat or to help de-escalate a threat in progress. One should only consider such retreat if and when it can be carried out safely to oneself and others in one's party.
Now the issue the OP raised also introduces another question. Suppose the incident goes down as described. I believe in most states, the laws regarding the use of defensive force, up to and including deadly force, say something on the order of this. You may use whatever force is necessary to stop the attack against yourself but it must be the minimum force needed to carry this out. In other words, you may not viciously respond to a pushing incident with blows serious enough to break bones, blind your attacker, and/or cause massive and permanent damage. Please correct me here if I am wrong.
In the OP's example, the GG raises his shirt to display a weapon to some BG's who are advancing on him in a threatening manner. At that point the BG's had not visited any harm against the GG and neither had the GG responded with force of any kind. So in a way, it was tit-for-tat. A verbalized andvisualthreat was met with a verbalize and visual response. One might say the two actions cancelled one another out.