Hermione didn't risk peeking around the corner, but she kept her attention focused on the two voices. Paul stepped out of view and a moment later Chiron spoke about the sword. She listened with interest despite herself, and got a double surprise. She hadn't known Paul's real name was "Pavel" and the fact that the sword had belonged to Achilles was also interesting. 

However, the way Chiron introduced it gave her chills. She knew that once an item acquired that kind of history it was very difficult to go against it. And she did not want her friend's life to end in tragedy just because of a stupid sword. She was tell him it was too dangerous. Or maybe he would give it up on its own, or Chiron would make him?

However, then Chiron changed the subject to punishment. That was the moment Hermione made her escape. She knew by this point that the punishment wouldn't be death or torment so didn't feel as bad abandoning him to it. And it was, again, just instinct. She didn't take the front door, but instead slipped out the kitchen door as quickly and quietly as possible, praying Chiron wouldn't magically appear in front of her or raise his voice after her. She would wait for Paul to come this way and then hustle him away from the house...