She heard him muttering a bit but couldn't catch what he said. She knew this was normal Severus behavior, as he often got just as involved in assignments as she did and tended to talk to himself occasionally while working. She took a deep breath and decided to speak to him. She had nothing to lose. Well, her feelings could get hurt again, but she was willing to risk it because she missed him.
"Hello, Severus," she said politely, her heart beating faster as she anticipated his response.