I've watched the battle between Anakin and Obi Wan in ROTS lots of times, but it wasn't until I watched it in this video that I found myself asking...when Anakin was on fire, why didn't Obi Wan put him out of his misery? I understand that Obi Wan didn't want to have to go back to Padme and tell her Anakin was dead knowing that he was the one to kill him, but seeing someone burned alive....is a pretty terrible thing to see, so if it was me seeing a former friend now turned enemy screaming in pain because they were on fire, I probably would have stabbed him with my lightsaber