It was a readied action (http://www.d20pfsrd.com/gamemastering/combat#TOC-Ready) which let Ren go in respnse to the rat's movement, thus getting it off before they closed on her. She readied it during the "surprise" round in both the encounters. Note that readying an action also changes your initiative count to right before the action that triggered it, this her moving up in the initiative count, where she otherwise might have simply charged on the surprise round.<br/><br/>Because it hit, she got DR 5/Adamantine, and if DR completely negates damage (which it did), then the disease (and other accompanied special attacks that accompany the damage) don't go off (http://www.d20pfsrd.com/gamemastering/special-abilities#TOC-Damage-Reduction).