For your first question ... By twist, I mean working those stitches out of order. ("knit the knit st from left needle after the purl stich, then knit the purl st and release both stitches from the left needle")
Not sure I understand your last question
. If you have a rogue purl st, it won't be "wrong" per se; but it also won't be as the pattern is written
because you shouldn't have rogue st to begin with. In row 1 you have a K1P3 pattern, but in row two that pattern is offset because she begins with P2 instead of 3. But the twist (working the stitches out of the order) is what realigns the K1P3 pattern in subsequent stitches. The row by row realignment is essentially what makes the knit stitch continually move to the right. So you can't have a rogue purl st; having one will stop the knit st from moving to right (and thus forming the pattern).
Make sense?? or ... less sense?