I have heard (very) senior Western karate masters argue that movements that are performed slowly in kata can or should be understood as throws or locks. This may or may not be true (the same masters can demonstrate these kata movements as throwing bunkai) but it should be noted that in the Wado ryu and Shito ryu versions of Pinan Yondan (which are much closer to the original) there are no overly slow movements.
For more background information on the Heian series of kata refer to Heian Shodan.
Master Kanazawa performing Heian Yondan