Do not force the door back
When a door is off the track, the panels are usually still hanging on the opener arm and the remaining rollers. Pushing, pulling or running the opener in that state bends the track, cracks the bottom section and can bring the door down on whoever is standing beneath it. Secure the area and leave the door as it is.
If the door is hanging and the garage is accessible, keep people, pets and vehicles out of the opening until it has been made safe.