If we go by that logic, then diving to prone on top of each other in the corner could be the next step.
There's no more voice files regarding a next step, so that's basically case closed right there.
What about the quotes regarding the navigation table, or the other from both Maxis and Edward we haven't heard yet?
Something tells me you have to ga to a certain location to hear one of the voice files, for example a room with a computer to 'patch' the application navcard.
Concerning the buildables, for the one in the diner you have to jump.. Maybe for the ladder you have to jump as well in order to put it somewhere.