In the east chamber, there are two gaps in the perimeter of roaches; one to the northeast and one to the southeast. You want to start at the one to the southeast, with your sword pointing southeast.
×From there, move southwest and point your sword southwest. Then move northeast three steps and point your sword northwest. Full spoiler ahead:
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×After that, move NE, NW, point your sword N, move N, point your sword NE, move W, point your sword E, move NE, point your sword SE, move NW 3 steps, point your sword N, move E, S, SE, NE, N three steps, and you're at the checkpoint. But don't forget to trip the lower pressure plate before you kill the roach!