Blade storm takes a while to do, and the enemy you are facing has an opportunity to get you while you are doing the combo. There is a solution for this, alot of PVPers do it, but I thought I would share it.
After you press 4 or click on blade storm, immediately press esc to put the weapon away
You can take the weapon out right after you press esc. youll stll hear the sound effect after you press esc (unless you dont use sound.
Hope this was helpful for everyone, I know it helps me
BTW, you can do the same thing with vipers nest
just press 5, or click on vipers nest, then press esc