To release the ratchet adjuster you need to lift the pedal, AND push the quadrant(adjuster) forwards to disengage.
It sounds as though it is working as it should from the above, and no you won't be able to pull it from the box end, as the spring takes up the slack in the cable.
A loud click with a new cable is just taking all the stretch out of the new cable, you'll know when it's buggered as the pedal will just hit the floor when you press it!!
tabetha