Mirror and the Light, ending?

[peaceanddove]

Absolutely loved it and cried at the end but a bit puzzled by the ending. Obviously he is executed but the last couple of sentences about him 'groping along the wall looking for the light' confuse me. What do you think Mantel was trying to convey here?

Try listening to the Radio4 version - you'll only need the end of the last episode.
Very moving.

I thought he was moving towards the afterlife, finding his way to the light of the next world.