Make sure your shoulder holster points down.

Some people are confused at why russian troops do all these rolls. I believe these originated with the Spetsnaz (Elite Soviet Troops), but why would they do this? Can they actually dodge bullets? Well no... you dodge where the enemy is going to put a bullet, your center of mass...
Some of the rolls are viable. You must remember that Special Forces are not often going against the enemies best shooters, they are strategically deployed to a large forces weak spot, which is most likely weak in part because the people guarding it are not amazingly proficient. Going against less proficient combatants a quick duck or roll out of the way can improve survivability. Not a lot mind you, but we do a lot for that extra %1 to our survivability. Special Forces vs Special Forces however…
A reason it might survive in training (apart from changing your velocity relative to a potential enemy shooter), is that it scrambles your balance a bit, and forces your mind to re-take-in the situation. The mind normally takes in one image, and provides to the rest of the brain any large and noticeable changes, if you jostle the image around enough you can prevent this and get all new data from your eyes. Mind you, in an actual combat scenario the fight or flight response would automatically up your perception to it’s maximum, so this can be seen as a method of providing confusion and disorientation that is common (or if not common, common enough to warrant training to counter) in a large combat zone during training, letting the soldiers know, if just a taste, what combat is like.
Another few reasons are physical in nature. It displays the physical conditioning of the soldiers, just try rolling all over the place, exhausting! It prepares the body for quick falls and blunt impacts, the type of thing that is common in combat.
As for the flagging and waving around of the rifles, Russian and former Soviet militaries don’t really seem to care about all that. Western Forces and gun enthusiasts in general are paranoid about it, and with good reason! Perhaps because we have better statistic gathering and know how many people were lost to friendly fire in ww2 (a large source of statistical information), while they did not have such luck or time to gather data while they were beating the Nazis for us. Either way, it has not been a problem for them, so they have not fixed it. Leave it alone, and ask them nicely to not point their guns at you. Then make sure your shoulder holster points down.