why would sarah pursue bear after witnessing the crazy actions of freaky nikki ?

so after some thinking i just can’t help but think about the fact that sarah , continued to admit she had feelings for bear and even went as far as kissing him up until the tragic event we know ended up happening . what i don’t get is why would she do this even after literally seeing how crazy nikki was acting when they all gathered at ian’s house ? i had thought she was an intelligent character and was even asking why they were dating but then she had feelings for him which came up out of nowhere . i genuinely don’t understand why she would do that ? like if i knew a guy had a girlfriend who was incredibly mentally ill or had some kind of possessive tendencies i am running the other direction no matter how much i like him . that’s also why her death wasn’t that surprising to me . to take it further she met him in a car late at night originally at a park but presumably near their house where they would easily be caught by nikki ? she should have just texted bear and tbh she could’ve avoided dying that way until unless nikki ended up finding out they were texting and still decided to kill sarah . we also know that nikki was aware that sarah liked bear and even told him that and bear continued with lowkey having an affair . i don’t feel bad for bear at all at this point and he is truly despicable and beyond cruel for me . as for sarah. , if she had been a bit smarter and stayed away knowing something strange was going on , she would have likely prevented her death but alas that wasn’t the case . she should have realized something was terribly wrong with her after nikki’s reaction to them almost kissing at ian’s house . i know this is just a movie but it’s important to be situationally aware of what’s going on and couple dynamics .