×
There may be other ways to do it, but the way I found was this:

You need to leave one group of queens alive and then get the slayer against the wall. You want your swords to be crossing, like so:

 / \
B   S
WWWWW

This can be achieved by:


Now you simply walk towards the Slayer and he'll retreat. When he hits the force arrows backed by roach queens, he has to move NE, and you move E and get him with the sword.

×

     /  \    w
    b    s  ww
wwwwwwwwwwwwww

In this position the slayer will retreat as Beethro approaches, what happens in the corner is the interesting part.