a quad copter will not be controllable once one motor fail.Even if Solo were spinning (as shown in that video on Athletic Quadcopters) due to a failing motor pod, at least if you could perform a somewhat controlled descent to a safe crash/landing point that would be very beneficial. Obviously it's better to lose the copter/camera and hit a safe point on the ground vs the copter dropping uncontrollably into a more vulnerable object. Perhaps it's just not technically possible with Solo.
the only way to control a quad is when the remaining motor on the opposite side of the malfunction motor is able to spin in both directions via a corresponding flight controller software.
Not possible with Arducopter to my knowledge and so not possible with Solo.