She is on a 19min timer.
Including named/PH, there are 4 total mobs in the room. Three of which are normal mobs (or the named)...the fourth - a Mistmoore Guard spawns on the landing in front of the Bath.
Three things to note about this mob: First, If you let it spawn and do not aggro it (be invis) it will eventually depop and Xicotl will spawn in its place. This can be a surprise as he is higher level than all the other mobs in this room. However, if you stay invis and do not aggro him, He will depop and a Mistmoore Guard will respawn in his place. Second, although this mob is much lower level it will run at around 47% Health. If you fight it on the landing in which is spawns, there is a good chance you are also going to aggro all 3 mobs that spawn in the bedroom next door. So what I did was aggro it, pull it to the Bath side wall, and nuke it when it runs. Doing so will not aggro any other mobs and you should have enough time to kill it before it goes through the fake wall. Third, this mob is on a much shorter spawn timer. (about 8 or 9mins). So you will see it at least twice before named spawns.