However, systems are in place to ensure that animals and keepers remain apart at all times.
But at some stage this failed and the animal and Ms McClay came together with tragic consequences.
Police are now working to establish whether this was a result of human or technical factors.
Mr Gill praised his staff, adding: "My thoughts are purely with Sarah's family and friends and very much with my staff, who have been ripped apart in the past three weeks by the untimely deaths of two of our young female staff."
Ms McClay's death was the second tragedy for the park this month, after another employee was killed in a road accident.