Semper Fi, Cannon Cocker! It's one of many very bad possibilities.
Have you read Matt Bracken's (Travis Mcgee's) books? That is the horrific scenario with which he starts his 1993 book, the first in a trilogy.
This is from the Prologue of Travis's 1st book, Enemies Foreign & Domestic. Excerpts are online.
PROLOGUE: OPENING DAY
The home team was set to receive the kickoff of their season opener. The 80,000 football fans packing the stadium were on their feet looking down at the two teams lined up on the verdant green field. It was a mild September Sunday in the Maryland suburbs of the nation's capital, and every seat was taken by loyal maroon and gold wearing fans who were hoping to see their team improve last season's dismal record and make a run for the playoffs. The crowd noise reached a sustained roar as they watched the kicker trot toward the teed-up football, they saw the two teams rush at each other, and they followed the flight of the ball high into the air.
In the midst of this jubilant bedlam, in the center of the western end zone upper deck, a forty year old architect from Annapolis was struck by something on the left temple. He immediately collapsed forward, spurting blood over his friends and several other fans as he fell across the seats below. His shocking injury occurred while the football was still arcing through the air and down the field, so at first the louder screaming of the fans surrounding his crumpled bleeding body went unnoticed by the rest of the crowd around them.
Every two seconds a similar scene was repeated with horrifying variations across the western upper deck stands, as one fan after another was dealt a sudden bloody wound to the face, head, neck, shoulder, arm or chest. A few victims were killed outright, and some were only slightly grazed, but many received searingly painful wounds which caused them to shriek and jerk and fling blood in all directions. Every two seconds another tableau of unexpected violent trauma was created, sending out radiating bands of fear as the shouted word spread from mouth to ear among the trapped thousands: sniper! The waves of horror emanating from each new victim spread and merged and multiplied until the entire western end zone upper deck section became engulfed in seething animal panic.
A minute after the first victim was struck, with the kickoff returned to the twenty yard line and the home team huddled to pick their first play, the continuing frenzied crowd activity in the western upper deck stands was noticed by several cameramen around the stadium. The perplexed stadium video director selected a close up scene of some of the over excited fans and switched that camera onto the stadium's two jumbotron screens. They immediately showed a house-sized image of a woman, her mouth open in an unheard scream, vainly using her hands to try to halt the flow of blood from a man's face.
The rest of the 80,000 fans saw the ghastly open wound and his blood-covered wife on the fifty foot tall video screens, and the panic began to spread from one end of the stadium to the other. Police radios crackled with reports of death and injury, police marksmen dashed out and scanned the stadium's upper tiers and light towers through their binoculars and rifle scopes. The sudden appearance of black-clad police marksmen with their rifles shouldered was noticed by mystified fans throughout the stadium, adding depth to the rippling fear.
Complete panic erupted through the western upper deck as the realization spread like a wind-whipped forest fire that an unseen sniper had them in his deadly crosshair gaze. Six thousand adrenaline glands pumped out their ultimate fight-or-flight hormone. Unthinking mob psychology seized the crowd, and nearly all of the fans who were penned up in the killing zone stampeded down the steps and over the chairs. This fear driven horde charged straight over the smaller and slower fans in their desperation to reach the perceived safety of one of the four exit tunnels.
It had taken well over an hour before the game for six thousand cheerful individuals to fill all of the seats on the steeply sloping upper deck. Many of the fans routinely grew dizzy and flirted dangerously with vertigo while climbing the concrete stairs, which were as high and as steeply pitched as the roof of a cathedral. Now, gripped by primal terror and racing down to the exits, the thousands of fans attempted to do the impossible, they all attempted to escape the unrelenting rain of bullets in less than a single minute.
Police, paramedics, security personnel and the just plain curious were just beginning to rush from the stadium's inside concourse through the tunnels to the stands when they ran headlong into the leading elements of the outpouring human tide. This slowed them enough to precipitate immediate jams at each of the four exits. But the terror of the fleeing mobs in the stands above the exit tunnels did not abate as the bullets continued to fall, and the crush began in earnest.
A hundred tightly pressed bodies, propelled by fear and assisted by gravity, pushed hard against each unlucky person already wedged against the safety railing at the bottom of the upper deck. The rails bent outward as the human avalanche gathered momentum, and then they buckled and victims began to tumble over. The falling victims were still holding tightly onto those above, pulling them over as well, and the solid cascade began. Dozens and then hundreds of linked victims fell past the VIP sky boxes, thudding down onto the fans packed into the lower stands ninety feet below.