I have been trying to gather enough memories of  my strange experience to understand how it was possible for me to fall on my face on the cement sidewalk twice, be coolly aware that my head was bouncing on the cement and not feel anything. This in an effort to answer your question, and mine - 

  How do you explain that?  

I have also to add  that i felt nothing at all when the whole experience started with me slipping on a loose piece of cement as i reached for the van's door and falling  in the space between the curb and the side door step getting stuck there for quite a  while as  I can  assume now by reconstruction. Then, I was in a state where time seemed indefinite and I was  only conscious of my plight , my body out there somewhere stuck and nothing else. Another factor to consider is that my HG was down to around 45.  So I went over the event in all details and I came to the conclusion that at the time I must have been  both alive and dead. Or teetering on the border between these two states. in fact , now that my HG is up to upper 60s, maybe even low 70s, I feel well and lucid enough that I can rather confidently conclude that I have been hovering in this quantum state, in and out of the box as it were,  for a while now.. Today I am more on the side of the living , so I am exploring this and cross checking my recent experiences in the light of the Copenhagen Interpretation.... I am a part time Zomby!