This is going to be a long one. Please tell me if I am wrong in my assumptions about this.

In October we got a new roommate. She had been a friend of mine over the past 6 months and we were getting along great and she also got along with my friend and current roommate over the last 2 years. We were looking for a third roommate for our new apartment and she also wanted to live with us. I could tell from the start that she was a more “emotional” person than me. I consider myself a very chill, “think before I act”-kind of person. While with her it was a lot of crying or sudden burst of anger for seemingly small things, but she also got over it quite fast and was happy again so I didn’t think much of it. Already from the start there was some scenarios where I thought she was overreacting or being irrational. For example breaking down crying in the kitchen for slightly burning a cake or yelling at me for “making her” have her birthday party, when I thought I was just encouraging her to do something she wanted to. She ignored me one full day because I had made her feel stupid for not being able to open a dip package, while what I had actually meant was that those things are really hard to open. It all went to shit in January. She started to ignore both me and my roommate for about a week. Didn’t answer us or just looked pissed if we said hi or what’s up. We went (separately) to a dinner at a friend’s house where she proceeded to not even look at us the entire evening. The day after we tried to sit down with her and have a conversation. It turns out she was mad about a situation the week before she had had with my roommate. She had complained about the heating not working and my roommate had said that he had called the repairman but there is nothing more he can do at the moment. Somehow she had taken this in the wrong way and was expecting an apology. After this me and my roommate had a convo and decided that we have been walking too much on eggshells and didn’t longer feel comfortable in our own home since this would happen every few weeks and we told her the follow day that she needed to move out. Ever since she had avoided the apartment coming in after we go to bed. In texts she is going between us being unfair, terrible people and she being a terrible person that needs to disappear. We have said that we are not throwing her out on the street, but that she needs to start looking for a new place. Yesterday she sent me a long text calling our treatment of her cruel, apparently my roommate had taken a shower in the time when she usually uses the bathroom without thinking about it. We are lost on how to handle this. We keep telling her that we don’t hate her, but her behavior has just been affecting us too much and thats why we want her to move out. How do I handle this? Am I totally out of bounds thinking she might have BPD? Since she is living in our apartment without having payed a deposit I am scared of how she is handling this. Don’t like to think that she can get violent, but she has acted very irrational in the past. My words aren’t getting through and I am lost on how to help her and I am scared in my own home.

Additional info: she does have a strained relationship with food, and doesn’t eat that much. We have just tried to handle that with being healthy examples rather than criticizing. She has also mentioned that her mom has called her fat and wishes she would get a nosejob in the past, which also sounds horrible for a parent to say.