My read on this is the gun wasn’t part of a prank, per se. The prank probably was to startle or confuse somebody, who reacted by pulling a gun, not knowing what he was up against. The prankster(s) didn’t want the subject of the prank to get in trouble, and lied. The lie was discovered, a new story was told, and deemed true. LE said the shooter didn’t break a law, but Sam did.
Nobody knew the gun was coming out due to the prank. Just my take.
This 100% Add into consideration Iowa's adaptation of the stand your ground law there is no legal recourse for whomever the shooter may be. Sam misled LE to save a buddy, bad choice, but shouldn't, and will not in my opinion, lead to a career death sentence. Hope he comes back totally healthy and we get to see a competitive March between the programs