It appears that as long as anyone is inside the house the ghost women spawn infinitely. You have to get back outside to get them to stop spawning. However, they always follow the exact same path and come at a predictable interval. Your best bet to avoid losing money is to only try the house when there aren't many zombies and to move slowly and methodically. Ray Gun mark 2 kills them easily hip firing but if you aren't fortunate enough to have one of those carefully headshotting them works very well also. Each time you get to a corner wait until one appears and then kill it and quickly round the corner. You don't want to walk into one unexpectedly just as it gets to the corner. It's tricky but very dooable to clear the house without losing any money.
Time magazine's Man of the Year in 2006! Really. Google it if you don't believe me.
She keeps coming at you until you leave the house, from the maze end or the front. The best way to avoid her is to anticipate her spawns, since they are the same every time. Take your time and you'll be fine.
Also, aim assist will not target her so you have to be a bit accurate. Which, if you anticipate her spawns, will be easy.
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