Serious situation need serious advice

Stephanie • Mom of a 2yo & 5 angels.

So my boyfriend and I have rooms mates living with us who are a couple as well. The guy A today got pissed because M the girl wouldn’t wake up to twist his hair at 7am. Well since this morning he’s been a complete ass to her. Told her to get her shit and leave and that she was dead to him. When M and I got off work (We all 4 work at the same place) we ran to the house to get something and was coming back. Well we was sitting in the car smoking a cig waiting on 5 to go in. He come storming out the building. Yanked my car door open was about to hit her and pull her out the car cussing up a storm. I told M to get back in the car I was taking her home when A walked away. As I was pulling out A come back out the building wrapping a wrag around his hand (he was about to bust the window to get her out the car) she willing opens the door to get out. He is threatening her and yelling at the top of his lungs. Cussing and everything else. She looked at me and told me to leave. She was going to be ok. I didn’t want to leave but the look on her face when she said “please just leave” I left. On the way home crying because I’m scared for her. I want to go back and get her but my boss (who is also a cop) said he has it. If he needs me he’ll call me to come get her. I’m just so worried. What should I do?? I told my boyfriend if he brings this home A is gone. He isn’t allowed back at the house anymore.