That's kind of the point of the post immediately before yours. When Beric was raised by Thoros the first time, he wasn't really trying to do it, in the sense that he knew it would work. He rather expected it NOT to, as his faith was largely broken with Beric's death, and yet it was that LACK of faith that was rewarded with new life. Mel finds herself in a similar situation. Perhaps, suitably desperate for any kind of positive, she reaches for something she doesn't actually think can or will work.