The ET302 crew was also trying to re-enable the autopilot as seen by the auto-pilot alarm indication in the data traces.
In any case, they did not have enough altitude to invert the plane. The plane does not have sufficient roll authority to do a snap-roll and not enough altitude to make up for the loss when, in the middle of the roll, the lift from the wings is no longer resisting gravity, but is pointing horizontally. Normally the roll to inversion is started with pitch up to avoid altitude loss, and is often done in very small planes where the side of the fuselage can supply significant lift.
There was a real life crash of an Alaska Air flight that "Flight" was modeled on.