BGutzman has it correct.
Because of the manner in which the Ezell appeals opinion was rendered, they are looking for judicial recognition of the right to carry. Any specific manner of carry is not at issue, only that it is part and parcel of the core right to self defense, as laid out in Heller.
By using the irreparable harm argument (as used in Ezell), they have just bypassed the next 6 to 9 months of briefs and counter-briefs (MTD, MSJ's and such).
Even if they lose at district (on the motion for injunction), they will be fast-tracked at the 7th Circuit.