Sure. You're right the large interior pocket is covered by a flap that's secured by clips but you can also roll that flap down and secure it with a velcro flap as seen here:



You can see the other bit of velcro on the flap that covers those two quick-access cargo pockets:



My mini krypto ulock fits nicely in to one of those pockets along with some cables.

Inside the zippered compartment:



There's a large pocket with its own zipper (bottom), a large opening (middle) and finally three compartments that are accessed via another zipper (top).

That's a blackberry on the right in one of the three compartments to give you some scale. The compartments aren't that shallow; they're about twice the height of the blackberry.

I love it. It's incredibly well made and will likely last forever. One thing I don't get is the website says the cross-chest stabilizer is detachable, but on mine it clearly isn't. The main strap can be attached so you can wear it over either shoulder, so it would make sense that the stabilizer strap could be switched too. I really should email mw about that.

I hope that helps!