First of all, Central Park at night is not scary.  It's a largely peaceful, and it's a photographer's wonderland.
Zim guides you to spots in the park where you can learn and practice new ideas.   She brings a depth of knowledge, a wealth of patience, and a mentor's  counseling skills to the task.   
She patiently walked through the why's and how's of night photography and allowed me to practice, fail, and practice again. I left with my head swimming in new techniques and insights, hoping to be able to remember and re-use what I learned.       
It was an unforgettable couple hours.  Well worth the time.