I believe you have left a crucial factor out in response to this problem - body heat. While the wind may create a slight resistance, it also helps the track runner's perspiration to evaporate, thus cooling the runner's body. This elegant cooling mechanism is missing in many indoor treadmills, where the managers neglect the importance of air circulation. So what the runner is experiencing is more likely to be heat exaustion than boredom.

I suggest that person to ask the gym manager to provide the treadmill room with a circulation fan. If they refuse, then you can bring your own. If not, try choosing a treadmill near the AC vent. This should help significantly.