Darius wore the same Carapace armor as the rest of his squad on his mission, and left the power armor and heavy bolter behind.  (at Baromir's request, in order to blend in).<br/><br/>Jason already has a best quality set of Storm Trooper armor... which gives "full" armor coverage just like a flak armored suit... so if he had to chose, I'd say that's probably the better choice.  Neither are void sealed, however, last time I checked.  Sure, wearing a void suit underneath works... but if they get damaged, unlike a suit of power armor, you can't patch them very easily... which makes power armor a lot more survivable for any trouble you might meet while in a vacuum.