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Can someone please explain the 3rd and 4th indented rules to me?

I diagrammed the 3rd as S>P ---> M>S>P and the 4th as M>S ---> M>S>P .... which is weird, right? I got through everything up to number 11 correctly, but then I think that some inference I'm not picking up on from the combination of these two rules kicks in and I'm not sure what exactly that is.

Any help would be greatly appreciated, thanks!

Taking the contrapositives of these two rules reveals that there are only two possible orderings (M - S - P and P - S - M) of these three variables:
#3: S - P → M - S (M - S - P); S - M → P - S (P - S - M)
#4: M - S → S - P (M - S - P); P - S → S - M (P - S - M)

You can then create two scenarios by combining this inference with the first two rules.

Thanks!