At the Vajrayana level the teacher becomes important. Up until the Vajrayana level we could read ourselves up on wisdom in books. At the Vajrayana level it’s important to have a connection to a teacher who can show us the direct and fast way, the Diamondway or the Vajrayana way to enlightenment. We now know about the nature of suffering being taught to us at the Hinayana level and we know about the wisdoms important to cultivate at the Mahayana level. And at Vajrayana level you’re taking a speedboat with lots of others towards enlightenment. The speed is fast and the realizations of the teachings appear direct through the teachers wisdom being conveyed. A kind of safety net is needed at this level because of the fast speed, and therefore the teacher is there to guide, protect and share wisdom.