Hi. I wanted to know if there is a way to get into the vent on the bank..

Getting into the vent doesn't really help you through the mission. While you're in the glass room be sure to delete the camera archives. The only way that I've gotten into the vent is from the outside. Go through the presidents office, jump out the window and grab hold of the small edges until you reach the ground. Take out the guard walking around outside, go up to the doors (don't worry, the camera should be off if you shut down the camera system in the glass room). To your right there should be a drain pipe, climb it. When you reach the upper platform, on your right there should be a vent, climb in and it will lead you to the glass room.

After you've entered the bank and gotten past the retinal scanner door, go around until you pass a guard shack and come to double glass doors. There is a camera to the right after you go through these doors. Shoot out the two lights and climb up the pipe across from the camera. Enter the crawlspace and you'll come out above the security booth. From up here you can access the computer with your EEV and disable the fan and avoid having to use the keypad to get into this room.