Now...you say that, but someone posted up saying that balls would be around 20 feet apart at 15BPS...I spent ages researching how to calculate deceleration on a paintball...got bored.
a=-kv
where a=acceleration, v= the velocity (so decelleration decreases with velocity you may observe), and k=the constant of resistance which you'd have to work out using fluid mechanics and the area of the paintball's surface.
Once you work out the constant it's a matter of differentiation (calculus is fun!) to work out the distance travelled and the velocity at any given point. Or you can fudge it by replacing "a" with "-kv" in the formula S=1/2(a **** I can't remember the rest. But you get the idea. It's too much effort. If you're still interested then there's your starting points though lol.......... What? It's all a moot point though since, if you assume all things are constant (which they rarely are, but hey), then the time interval between balls will be the same as when they were fired. So you still have very little time to get out of the way. And all of this is assuming that you're shooting lasers/ropes/testicles very accurately.
Oh yeah, my marker rips and is god's penis.........yeah 8)