You must have misread, awolfromlife. The adept power as well as the holster decrease the threshold
to 2, neither one lowers it
by 2. So a quick draw holster would not benefit a character with the quick draw power.
On the other hand an adept could put his weapons into concealable holsters and still have a threshold of only 3. Additionally the adept can quick draw an assault cannon or a battleaxe.