How to remove the passenger power rear door

Are the latches releasing at all? Is the door stuck completely closed? IF that's the case , you will need to remove the inner door trim (probably breaking it) to access the latch assembly to release or unlock it. Power locks I presume?

If it's like the Honda, the outside where the roller slides there should be a space for the slide to move along the body. You should be able to access the cable under that and cut it if that's all you want. You'll have to remove the rear trim panel to remove it from the motor.