Leaving a Master's Degree Early for a Doctorate Degree?

I am currently enrolled in my fourth semester of my master's degree program in psychology and this should be my final semester. Due to issues stemming from myself and my relationship with my mentor, my thesis has been lagging behind the rest of my school work and I am just now preparing to defend my prospectus. While I am currently awaiting to hear back from Ph.D. programs, I am starting to consider an alternative plan to completing my graduate education and was wondering if anyone could help shed some light on this matter?

On the off chance that I get accepted into a doctorate program I am wondering if it is possible to leave my current graduate program without completing my thesis and proceed to enroll in said doctorate program? Are Ph.D. programs going to frown upon this decision? Will they still allow me to join the program? My present thesis is really not related to anything remotely close to what I want to study and I have had a very strained and borderline emotionally abusive mentorship experience at my present program and would prefer not to continue working with my current mentor if possible. I am assuming I will have to complete a new master's thesis on top of a dissertation while completing this possible Ph.D. but I just wanted to know if the option to leave one program and enroll in another is available? I would much rather spend more time completing a new thesis with research I care about and a mentor who will (hopefully) not be as abusive rather than finishing up a thesis late at my present program.

Thanks!