As Mary Ann is dying, Kevin is holding her close to him, hugging her. From the behind shot of Mary Ann, you can see, sticking out from behind the right side of her neck/hair, is a tube and the yellow packet that held the blood/pump.
During the beginning of the film, Al Pacino and Keanu Reeves are on top of the office building. Pacino is promising money, clients, and power to Reeves if he joins his firm. This is a reference to the temptation of Christ where Satan took him to a mountain and showed him all the cities of the world and promised it to him if he bowed down to him.