Push Button for Emergency

In the park behind where I live, there is a rather dank and, depending on one's perspective, creepy tunnel that allows pedestrian traffic to travel under a highway. Big red buttons were installed at about a third and two-thirds of the way through. I suppose one is supposed to press one of these in case of emergency. However, there are no instructions nor explanation of what to expect. It looks like these were installed simply to assuage the fears of us who have seen Harry Brown and Irreversible.