Tiltbed. You are right if a rollover seems close take the downhill. A rule is "up is roll over and down is roll out". If the tractor does roll it is far better for it to roll down hill first rather than up hill and then downhill; particularly an unseat belted driver has a much better chance with the tractor rolling away (downhil) than back towards the driver's only escape path if turning uphill.

The concept it to turn away from the loss of control motion, e.g. counter steering a skid in a car. Turning down is the counteracting of the roll.

The answer is to avoid the role over and deal with a run away;
also serious, but considerably more controllable than a roll over.