Explain how Ruth and her friends in Ruth fielding at snow camp come to realize that a bull is chasing them?

There playing at the park and an old man yells theres a bull and you and your friends run and you find a playground and climb up a slide and stay there but it breaks and you climb over a gate and run to the police and they take care of it!

Someone yells that there was a bull chasing them abd they turn around and realize that there is a bull chasing them