I think @Hodders would get some serious burns if you chuck a piece of duck fat-side down into a scorching panHot hot pan
Duck has so much fat you need to render it down slowly. Most recipes call for it to be cooked from a cold pan, no? I'm not sure what the 54c in SV does to the fat, does it render it out at all? If not and you chuck it in a searing hot pan, you'll get a thin layer of crispy fat hidden by a chunk of un-rendered fat underneath. Probably hence why it wasn't crispy as a whole. I'm not sure what the answer is though, render it in a pan first, then SV then sear? (dunno)