If you can shoot left-handed, you can stealthily switch the gun to your left shoulder, turn, and shoot. This involves way less movement than rotating your whole body and trying to shoot right-handed. The real secret to shooting left-handed is simply to practice. Dry firing a few times certainly helps, and so does a red dot sight, which allows you to shoot with both eyes open. When you're able to shoot with your off hand consistently, you might have a different point of impact than you do with your strong hand. Take note of that and make sure to compensate in the field.