Ok, having seen the whole episode, my take is that, in Rumple’s understanding, Pan, as an immortal, could not be killed so long as he was magically empowered, so he instead stabbed himself and Pan with his dagger. Since he was stabbed by himself and not someone else, the Dark One’s curse overloaded and destroyed them both
Pretty much. Hence the glow-y light. I also think this means the DO’s curse was destroyed.
[adrotate group="5"]
"He was a lot of things to me" "The only conclusion was love"