Scene Context: Wayne falls on the final steps of the ladder, and Turbo practically forces Alex to maintain three points of contact.
Essence of the Phenomenon: In a heavy spacesuit, even a simple ladder descent is not trivial. Due to restricted joint mobility, an altered center of mass, and surface dust, losing just one point of contact can instantly turn a step down into a dangerous fall.
Scientific Basis: NASA's EVA architecture requirements consistently emphasize the importance of handrails, tether points, and meticulously designed translation paths. Their purpose is not convenience, but mitigating the risk of falls, slips, or loss of body control while suited. In partial gravity, this is just as critical as in microgravity.
Current Limitations: On Mars, a person does not "float," but neither do they move as they would on Earth. Partial weight, loose regolith, and a bulky suit create an environment where even a minor slip on a rung can result in a hard, dangerous impact.