Sandra relied on Beth more
Rather than the other way round which is strange considering Sandra was the older one. Even though Sandra did play the big sister and looked after Beth and they both relied on clung on each other I concluded that Sandra needed Beth more. For instance, Sandra seemed more unstable than Beth and during the separation scene, although Beth desperately struggled after they were torn apart, beforehand Beth tells Sandra "I love you" as if she had accepted their fate of no contact whilst being devastated. Sandra however would not accept it and desperately tried to get free to be with her sister. Beth also struggled but it seemed she wanted to comfort her sister as she always has done. At this point Beth could see Sandra was broken and Beth wanted to go comfort her because she couldn't bare to see Sandra that way in their parting terms. Don't get me wrong Beth was heartbroken too but the "I love you" makes me think a part of her accepted that they wouldn't speak for 10 years. Plus the last scene of her struggling shows her literally fall down in defeat. Sandra on the other hand would not accept this and fought the policeman till the end.
Anyway sorry to ramble (that scene really affected me) but yes it seemed like Sandra needed Beth more than the other way round. What's the psychology behind this? Is Sandra just weak and needs emotional support constantly? She made up all that stuff about her psychiatrist which makes it seem like she needs attention and to be noticed.
Please tell me your thoughts on this and the heart-wrenching separation scene. As you can see I completely over analysed that scene but it was just so raw.