I'm not questioning Theon's actions, I'm questioning the way it was so obviously signposted by the discussion about protection just two minutes before. You knew exactly what was going to happen, and to be honest, the final scene would have been all the more powerful if that foreshadowing hadn't occurred, and you saw in real time, his regression to Meek, and you realised - at the same time he did - what his motivation was for making the choice that he did.
Previous seasons handled events like this much better, and to me it just comes across as poor writing. They know people are going to tune in regardless as they've invested time already in it, so probably have become a bit complacent.