IF GS vomited blood, it would have been mixed with gastric contents. That would have been easily detectable by lab tests. If he aspirated blood, it would have had "bubbles" and the AA report notes those were absent in the spatter.
Most internal bleeding doesn't (and can't) result in vomiting. Only bleeding in the stomach can. Or in the case of liver disease discussed in a much earlier thread, burst veins in the esophagus resulting in swallowed blood that is then vomited back up. And when that happens, if the blood spends any time in the stomach, it changes into something that looks like "coffee grounds" because the digestive process has begun.
While nosebleeds LOOK alarming, most aren't and do not result in much loss of blood despite how it may look. (And at higher elevations, nosebleeds are common.)
If GS had suffered blunt force abdominal trauma, his spleen or liver could have been damaged leading to significant internal bleeding into the abdominal cavity. But he couldn't have vomited up that blood. It wouldn't have been inside his GI tract, much less inside his stomach.
JMO