It took everything in Mac to not run down the steps and shove herself into the vampire who held her master helpless against the wall. If the other two vampires hadn't come into the scene, the male seeming to be familiar with everyone, while the female Mac recognized as Rebekah's slave, Mac would have actually attacked the blonde.
But as it were, she dug her nails into the railing of the first-to-second-floor staircase, eyes glowing red, and fangs starting to elongate threateningly. Her claws are what kept her staying put, and some glimmer of hope that this other vampire would find a way to talk down the blonde who had Jack against the wall.
A very low growl escaped her lips, animal instincts starting to take over.