I thought Nancy was going to be buried at his side when her time comes.... perhaps it's easier than it looks, but how are they going to move that slab without damaging everything?
Heavy equipment. No problem.
They planned everything. Note the heavy duty railing around the sight. It wasn't there on Friday.
It seemed to me the slab was there before the President was interred so they had to remove it to place his casket into its resting place and then return it to its current position. I imagine some heavy machinery was used but if I am right it can be done and will only have to be done once again.