Could be alot of things, guardy behavior of the space/your room? Jealousy, displaced aggression, or it could just be a "bitch" thing,,Bitches when they fight can be nasty nasty.
I would never ever leave them ALONE together, you might come home to some serious damage one day
You might have her thyroid checked/vet clearance, while it 'could' be medical, I kinda doubt it, but I'd rule that out.
While it may be hard, I think trying to figure out what, if anything sets Tika off, and work on stopping it before it happens, could help, BUT, if it's just out of 'nowhere' this could be nearly impossible.. Tika has her reasons for doing what she's doing, whether they are rational or not, it's 'her' reasoning.
She sounds like she means business, and with that I would never leave them alone unattended..crate one of them when no one is around.
Sometimes dogs can just be bullies,,and sometimes females just don't like other females at points in their lives and are going to do something about it.
Sorry I don't really have any other suggestions on a 'cure'..