If you've ever played head to head people usually don't even get the sword. I usually murder the sword guy with a Plasma Pistol/Battle Rifle.

Of course Magnums(pretty much with anything), Sniper Rifles, and Rocket Launchers. None of which midship has. When the sword guy is in his little group(which is usually how he survives so long and gets that high amount of kills) then simply grenade the group. There are frags in midship, but I've been learning more lately about both types of grenades. I'd have to say that 10% - 15% of my most recent kills have been grenades, whereas I used to hate it when I was fragmented by them. They rule when you have a shitty weapon, and in groups.

Anyhow, my point being that the sword guy is far from invincible.