Premise 1: Darken Rahl has many wizards, etc, to attack people he wants out of the way.
Premise 2: Richard has been under spells before (some by/for Darken Rahl) which play with his mind.
Premise 3: Richard *still* has the box of orden because why on earth would they want to tie up that plot line?, which DR *really* wants to get his hands on.
Premise 4: Richard falls off a clifforsomesuch and wakes up to see his murdered father alive, and his turned-against-him brother very concerned.
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Conclusion: Richard is experiencing time travel.
*facepalm*