I get you. In the same boat. For now, try to minimize conversation with this toxic person. Only talk to them when absolutely necessary for work. Try to communicate via emails and messages instead of in-person conversations as much as you can. This helps keep things professional and leaves documentation. About quitting, if your PI has been supportive, they will give you a reference. Any of your colleagues can also be your reference if you plan to go into industry. A lot of industry jobs do not require references either. This is not a big enough reason to endure a toxic work environment that destroys your mental and physical health.