Yeah, you resumed it very well. There are many loving combinations with this card.
I think that if you shokwave the martyr, even if the damage is above 3hp, the dying effect goes after all the damage is dealt. So it won't pass to the archangel.
I also have another creature in the forge called Tomb | Grave (
http://elementscommunity.org/forum/index.php/topic,14278.0.html) that could be a great combo with it.
Grave becomes the first creature to die, so you can use it with Martyr this way: play Grave and Martyr, immolate Martyr (it becomes an archangel), Grave becomes a Martyr and start again. You could pay the Grave with the Soul Catcher. And also there is another card I did called Fiddlers Green here in the light crucible, that can bless the archangel (because Grave is not targetable).
Thanks for your words.