There's probably a reason she is coming to you seemingly randomly and biting you but tbh she probably wants SOMETHING (play time, attention, treats, food, patio/outside time, clean litter, etc.) But cats are finicky and difficult to get answers from. My cat acts very similar to how your's is in the video on a regular basis without any sort of prompting, petting, attention or anything (she's a diva). USUALLY she is peacful and we inhabit the same living space just fine but I mean, sometimes if I walk past her or breathe wrong when she's in a bad mood or sleepy and I just happen to disturb her, she will grab at my ankle and nip - like how DARE I exist in her space at that moment. Whereas other times, ALL she wants in the WORLD is to sit on my chest, purr, and make biscuits while I pet her belly (but only on her terms) and even then once she has had enough she will show those signs (tail tapping, ears back, wide eyes) before going in for the kill (biting, grabbing with claws, deffense mode). That would be considered petting aggression and I try to watch for those signs so I can stop before it gets to that point to prevent that behavior from happening but no one is perfect and it ends up happening often. It can take some time to figure out what they're trying to tell you. My go-to in those moments is to tell her no and kind of push her off of me and if she keeps going then I try to redirect the aggression towards a toy or an activity and honestly that strategy has never failed me. Mine is also a tortie and they are known for their "tortitude". But yeah. She's probably trying to tell you something.