I think it's cool. Probably one or more of the pteranodons flew the gyroscope in and they were busy devouring the previous occupants when the Indominous Rex broke out of it's pen and finished off the snack. Killing a pteranodon or two in the process before making it's way deeper into the facility where it waits for it's next meal. - See it just takes a little imagination to have fun at a theme park.