"The Masters? How would they know that she was here?" It must've been that her presence had been felt by the Sith. He wouldn't consider the alternative that began to nag at the back of his mind. No, she wouldn't fall. She was here to help the Jedi, that's why she disappeared. She would never JOIN the Sith! She was convicted, a follower of the Light through and through. At least, that's what he chose to believe. He would have to investigate later. For now, he had a rather arrogant Sith to deal with. 

"Weakness is a matter of perception, isn't it?" He moved to his left as the Sith assailant moved to her right, Yerbol not wanting her to gain any kind of advantage by leaping behind him. The chamber was small, but there was some room between the pillars and behind the actual tomb, but the entranceway was narrow and would have allowed her to leap behind him and deal a killing blow all too easily. 

"What you call useless and soft is what has driven your order and your Empire back into the shadows. You know, I've wondered..." He sidestepped to where his lower half was obscured by the crypt. 
"How much of your order is left? Surely your 'powerful' Masters are buckling at the pressure the Jedi and the Republic are exhibiting. It's not as if you people work together well. The infighting, the back stabbing...no wonder you would kill Lysa in cold blood. You're scared. You're scared of what's coming, the peace that will come across the galaxy...and I pity you for that. I really do." He was now behind the tomb, stepping back a few feet.
"I would give you a shot at getting out of here alive, but you won't take that chance, will you?" He then threw his lightsaber in front of him, hoping the throw would at least distract her as he leaped above the tomb, grabbing his saber mid jump and delivering an overhead thrust. The force of the blow would send her staggering, but then again, Sith had tricks up their sleeves he would have to be aware of. 

Unaware to both of the combatants, the wall across from the entrance was slowly beginning to recede...