This is a very interesting sentence! It's just the end of the paragraph. But it sums up the point: all the actions up to this point were because of this statement. This is something that has to be faced, no matter how bloody, no matter what camp, no matter what opinion, this is what medical students should do.

"The amphitheater buzzed." The first paragraph has already mentioned quietness, but the word 'buzzed' is used here. It highlights the sharp contrast and expresses the students' fear of cutting a dog's chest.