Man this guy must have had a really horrible lawyer (probably paid for by the state which brings up separate issues). By the small amount I've seen, this guy needs a jury trial and some mainstream media press.
Look at the entire sight and all of the videos. I don't know who paid for his attorney. May have been his family, or it may have been a federal public defender. Remember, this was a federal prison, so federal law applies. however, I don't know if there is such a thing as a duty to retreat under federal law and if state law (Louisiana) can be incorporated into this standard if there is no duty to retreat.
Tactically, the guy who sacrificed his mobility, by allowing himself to be trapped in a shower stall, is the guy who died. Had Eddie Branch cowered in his cell, is it reasonable that he would have died?