What could be wrong if your dog falls over when she shakes her head?
Unless this is a young uncoordinated puppy, this could be abnormal, like a neurological problem or problem with the inner ear and balance. Even if it is an uncoordinated puppy, it shouldn't happen frequently. The best plan would be to have the dog checked by a vet, this could be a serious symptom.
Yes it is possible, particularly if weapons, multiple attackers, or particularly bad falls are involved. Sometimes just getting pushed can become fatal if you hit your head the wrong way. Or if a student has an undiagnosed medical condition such a heart disease, they could possibly die from the excitement.