You ever wondered why people want a marker that can lay down ropes of paint? Now you know.
I think that this problem lies with your use of concealment and cover. The better cover you use the less likely the other guy can hit you after you take out his friend. Then you can just snap him out.
Use ROF to yuor advantage as well. Wait til they're both in range and you burn them both down before they can react. I can guarantee you a player will be more surprised if he gets hit with a hail of paint than if the guy next to him just take one ball.
Could we spell it correctly...please?
Take a look, you might be surprised.