I know! I know! The hurry was that Davis was advised by his top men, that if he drew first blood that Virginia would come in on the side of the south! Major Anderson had just stated to Beauregard’s messenger that he had three days of provision left and would then have to abandon the fort. That put the pressure on Davis to act. It would have been meaningless to Virginia for Davis to attack an abandoned fort.
Which “top men” advised Davis to seize the fort to draw Virginia into the Confederacy. Davis’s Secretary of State told him that if he attacked Sumter, the South would lose every friend they had in the North and stir up a hornets nest to boot. Lincoln’s efforts to resupply the fort forced Davis’s hand. Davis was not going to allow Sumter to be resupplied under any circumstance. To do so would have only kicked the problem down the road.