Translation of ergonomisch

A bystander who watched the entire scene all the time decided to help me. He was an older man, around seventy, but nonetheless he went to the oldest of these kids and slapped him. The boy was sixteen.
The writer describes this situation by putting the persons into a natural environment. On one side there was no shade and there weren't any trees, he says. This description can be interpreted.
We had coffee, played cards and waited for our guide. We had booked the tour with Handspan, so that we were confident that he would show up. In the end the guide was a 'she' and not a 'he'.