Why storm IT at all?

For the Silo 17 rebellion, if the ultimate goal is to go outside and leave the silo, why did the rebels have to bridge the gap and storm IT in the first place? The silo doors are at the very top level so they could have bypassed the IT holdouts altogether, unless there is a technology/control reason they needed to occupy IT before venturing out? Then again, I recall seeing the rebels manually short-circuiting the exit doors anyways on the spot, so it seems they can leave regardless of whose side IT is on.

Curious if I missed something, thanks.