The arena of the bullring is filled with sand taken from the beach. This is the classic soil for bullfighting. If you don't wear sneakers or sports shoes of some kind, the sand could cause falls and maybe put the runner at the mercy of the animals. Consequently, it is important to take note of the change of the ground, from the flagstone of the street to the sand inside the bullring.
It is also important to realize that entering the ring in front of the bulls it is necessary to turn either right or left. The bulls do not normally make a brisk turn on entering the ring -their instinct is to run straight ahead. A quick turn to the left or the right should bring you away from the danger of the bulls coming behind.
It is very important to allow the dobladores (guides who lead the bulls towards the pens) to do their work. These men wear a green shirt and have a cape in their hands. They shouldn't show the cape to the bull as is done during bullfights. Rather, they drag the cape on the ground and lead the bull in this way towards the pens. They must be left alone to do their job without being distracted.
There is also a custom among the runners themselves to give a beating to anyone who interferes with the bull while inside the ring or who hampers the work of the dobladores. A bad custom perhaps, but it does exist. So, as well as a fine you might also get a beating.
The bullring means the end of the running of the bulls. It is important to get away from the bulls and to be on guard just in case some bull turns back on its heels.