She probably missed because it was room temperature and not a strong heat signature.
It's "possible" that when she regurgitated, that she got some of the stomach fluids into her glottis that went down into her lungs. That's what they breath through when they eat, they also breath through it when they are regurgitating a meal.
Though I agree - anything we suggest is simply speculation, a necropsy would be the only definitive way to know what happened.