You sacrifice the old man get up and stand, sit instead. Because the body has a decent layout not robust as children or teens. If he stands and time the vehicle brakes may make him an accident.
You sacrifice the old man stood up and sat instead. Because older people have an unhealthy body of a child or adolescent. If he stands, then took his car brakes can cause accidents.
You sacrifice stand up and let the old lady to sit. Because of his old body is not strong as a child or teenager. If he stand there and when the car brakes he might have been an accident.