Many fights end up hitting the ground. If you are not comfortable working from the ground, then maintain a solid fighting distance and avoid in-close fighting as much as possible. Adding to the danger of ground fighting is the possibility of more attackers arriving, glass on the ground, weapons, and your most immediate attacker being much heavier, as well as numerous other factors. A grappler will have methods of closing the fighting distance with you, and taking you out of the range from which many types of strikes can be thrown solidly. In this case, make well-timed use of elbows, knees, standing submissions, reversals, makeshift weapons, and other such anti-grappling maneuvers. Be especially careful not to over-extend your strikes, or leave them extended for long after delivery, against a seasoned grappler.
When faced with an attacker who you suspect has a weapon, you will, of course, have even more reason to seek means of escaping the situation other than hand to hand combat. It is possible that if you comply with your attacker, they will let you alone afterwards. However, do not always be quick to believe that he or she shares your belief system; they could very well harm or even kill you after getting what he/she wanted.
The attacker may also be on drugs such as PCP, which would make him or her very dangerous to deal with. Pain compliance may not work as well against such an assailant; move defensively while doing as much damage as possible. Use the environment even more so, such as getting free to run and throwing things in his/her path. Also be extra careful of weapons the attacker is wielding. If at close range, attempt to stop the weapon from even being drawn. If this is not possible, dodge an attack or jam it as your opponent comes at you. Control the wielding arm, and strike at your opponent with your free limbs, head butts, etc. until you can disarm or subdue. It