To piggyback on your last question (About brain in a jar), the wording on that card seems almost the same as the old Havengul Lich from Dark Ascension except with instants and sorceries from your hand instead of creatures from the graveyard, and yet Havengul Lich can't let you cast things like that unless they had flash. What makes BiaJ work with sorceries that prevents HL from working the same way? Is it the "middle of the ability" part?
The difference is that Brain in a Jar tells you to cast the card RIGHT NOW. i.e. In the middle of the resolution of its ability, which is not a normal time to cast a spell.
Havengul Lich just gives you permission to cast the card from your graveyard this turn, but doesn’t make you do so immediately. Since no special timing permission is being granted, you have to obey normal timing rules when you cast that card.
