Well if it was not a slip fall then one has to wonder why Wiegman would lay down like that when he could have just crouched down bending his legs while balancing himself still on both feet if he wanted to change his camera perspective to lower ground.
Yes, I agree with you. There is No logical reason for a professional photog, that works for NBC, to be sprawled chest down across those steps.
Plus: (1) Wiegman Never said he was ever sprawled across those steps, (2) No Eyewitness ever has said that they saw Wiegman sprawled across those steps, and (3) There are No Assassination Image(s) showing Wiegman sprawled across those steps.
The Bell Film early/blurry copies led many members of the Old Guard JFK Assassination Research Community into rubber stamping what technology is now revealing to be a JFK Assassination Urban Legend.