Brennan became concerned when the blade and sharpening stone slipped, it would be unfortunate (yet fortuitous, a part of his mind whispered) if she were injured simply because he startled her. That was not his intention in the least. Brennan did not deal in threats and anger unless he had to, or he knew he was facing an enemy. As he learned in Orlais, 'you can catch more flies with honey than vinegar'. Why anyone would want flies was beyond him, as they were pests of the highest order.
She did not seem to recognize him, which was both a relief and a bit of a disappointment. He tried to convince himself that he did not want to be well known, but it went against his nature to sink into the sidelines. Stepping in closer to the light, he crouched down to her level. It felt strange to him to be towering over her while she sat. Even if she did stand, he knew he would still tower over her.
Compared to lowlanders, his people had been a bit taller than average, but she had to be shorter than average. He had even mistaken her for an Elf at first until he had seen her ears. Now that he was crouching, he had a close up view of how well she kept her weapon. He was impressed, as it showed dedication and skill. At her comment, he offered a less forced but lopsided grin, "Are you sure that is because they just can't see you on account of being so tiny?"
It was probably not the best idea to tease the person that he wanted to convince keep silent, but the idea that she might not remember him had given him a confidence that he otherwise would not have. That and there was something about her that made it easy to tease her. Oh, that was probably her height.