Exit Delay is the amount of time the system will allow for you to exit out of your entry/exit door after arming the system. It's factory set at 60 seconds for both partition one and partition two.

(A partition is an area of the system that behaves as its own system. A Vista 20P can have two partitions, but most installations only use partition one.)

Sixty seconds is just about right for most systems, but it can be adjusted to as little as one second (don't do it) or as much as 120 seconds.