I don't see how a study week would make such a huge difference in grade if you actually knew "most of the content quite well". Unless most of your classes have massively weighted (60%+ of total grade) finals and you're assuming the scenario in which a 93.0% (typical A cut-off) is reduced to an 89.9% (typical B+ cutoff). Considering that you're an engineering major and in your final year I can't imagine a normal (if any) grading scale anyways, in which case the professors (assuming they aren't meanies) would see that everyone suffered due to the circumstances of the earthquake and curve appropriately anyways.