Earlier, Theo had walked into the room ready to kick everyone out only to find Blaise pacing frantically. He said Crabbe and Goyle had both been called away urgently and by their bloodstained clothes Blaise had gathered the reason was not good. Hermione didn't even feel the smallest slither of guilt when Blaise mentioned Crabbe. Knowing his fathers desiccated husk was presumably leaking bodily fluids onto the dust covered floor of Bourgin and Bourkes. If anything, it bought her solace.