AITA for giving my MIL a fake doorbell camera password?

My (29F) mum and I are currently staying with my grandparent's house. They're 70s and my mother's plan is to stay here for 3 months and do nothing. She found a job 2 hours away and we've moved in. <br><br>I've been dealing with my MIL who likes to walk into my room to do her makeup while I work from home. I've asked her not to but she says I'm overreacting. <br><br>Today she texted me and asked me to open the front door so she could come in. I hadn't heard my mum open the door and thought she might be alone. I asked MIL for the doorbell camera code to check. I have to enter the code so the code is required. <br><br>She said she didn't know. I asked her multiple times but she refused to tell me. I said if I open the door and there's someone there it would be my neck. <br><br>So I took a screenshot of the code page with the code on it and sent it to her. I asked her to enter with the code. She called and yelled at me and told me I was ridiculous and to open the door. <br><br>I asked her why she wouldn't give me the code and she said I'm crazy. I'm recording all the conversations and will give them to my husband to play to her face when she's ready. <br><br>I think this might not be okay but I don't know what to do.