Super-defensive cat... But only in one room....

I come to this forum with a good amount of experience raising a troubled cat, but have never heard of nor seen behavior quite like I have over the past week. A bit of background first....

I live in a city, thus there are plenty of strays/feral cats running about. It seems my landlord had taken a liking to one specific long-haired calico and kept her fed, litter-boxed and warm in the basement until he could find a suitable home for her. That suitable home ended up being my apartment (my housemates, specifically, decided to adopt her, with my consent of course... How could I say no?). Being the only one in the house with any amount of cat-rearing experience, I've taken the lead in trying to get her acclimated to her new surroundings. (Quick note on my kitty experience: I adopted a cat, Bailey, somewhat by force, after he wasn't being well taken care of by a previous housemate and ended up needing a 3am ER visit due to a eurethral blockage. At the time, he was a skittish 10-12 month old rescue, presumably from a trashbag, as to this day, he is petrified of the the mere sound or sight of one... Having adopted him as a panic-ridden cat plagued with urinary issues, I've gotten him to be a very healthy, panic-free, affectionate, and all around fantastic now 5-year-old cat).

And for the rest of the background, unfortunately, I know very little about the new household member, Siska. What I do know is that she's no more than 1.5ish years old and came litter-box trained (probably an abandoned kitty as opposed to a feral one) and is seemingly healthy (minus the need for a bath and nail trimming but I'm hesitant to do either as to not cause too much anxiety so soon) though because of the holiday, she has yet to see a vet. I'm somewhat suspicious she might be pregnant, though she hasn't been in the house long enough for me to see any substantial changes that would definitively indicate that.

As to the issue at hand: Throughout most of the house, Siska is moderately affectionate and outgoing, which is surprising given the very new environment. This holds true in all rooms, and in all conditions, however, this does NOT hold true in the kitchen and only the kitchen. Whenever anyone walks into the kitchen, even if she's at the opposite end of the house, she will immediately bolt to the kitchen and begin stalking them and pushes them with her side. If one stands still, she'll move away and get into a defensive posture. When one starts to walk again, she'll either hiss repeatedly, attack the person's foot/legs with teeth and claws, or run in front of the person and yelp as though she's been stepped on when she clearly has not been. Upon leaving the kitchen, she'll follow the person into the dining room and begin crying. Typically, within two minutes of exiting the kitchen, she's back to her normal self. My initial theory was that she was defending her food, (which I thought may have been a scarce and precious resource when she was on the streets). That theory has been struck down. I moved her food into the dining room, but her behavior has not travelled with it and remains only in the kitchen. My next theory, which is difficult to test, is that she has some negative association with the kitchen in some way due to it being the first room she was introduced to when she was brought into the house. I'm not sure how much sense that makes, but I'm otherwise at a loss to explain it besides my final theory, which is her association of kitchen+person=abuse (by a previous owner). However, I feel if that were the case she would avoid the kitchen when someone is present rather than pro-actively run across the house to confront the person. (One final side note, she is the only cat in the house presently as I recently moved here and have not had the opportunity to move Bailey into the apartment. That fact seems to rule out any cat vs cat defensive/territorial behaviors). 

Anyway, I'm not sure if I'm missing something either obvious or not-so-obvious, but any insight as to any possibly reason or potential solution would be very much appreciated. I'd like to not cause her such distress, nor do I want to be dodging a hissing, biting and scratching cat because I want a glass of juice....

Also, being my first post here, please feel free to move this post or mention if I've overlooked something, etc.

Thank you all in advance! 

That is very different. The closest thing I can think of is when my Lucky would hiss and growl at the kittens in my bed. Not anywhere else in the house as a rule, or even the bedroom in general. Eventually, I realized he was possessive of ME because he was fine with them - even in my bed - when I wasn't around. But when it was bed time, he made sure they knew they weren't welcome by me. Although, they still slept there, just at the foot of my bed. Lucky was always on top of me to to my side.