I don't know that you could unlock the gate from the inside if you tried as is. An electronic gate could be programmed to do exactly as you would expect and open if there was an emergency. I believe, as was stated before, that that is also not the only way out of that area.
Plus, much like passwords, making everything the same is generally a Bad Idea(TM) I would vote, if we are doing a new system just the opposite. If there is a second level to disarm the alarm after entry on the new system, each person should have their own pin to activate/deactivate the alarm, using the card/code combo to be unique (you unlock it, you disarm it). As is, if someone was a member, and was 'removed' for any reason, they would still have a lot of access.
"The right to be heard does not automatically include the right to be taken seriously."
-- Hubert H. Humphrey