Complex sentence: The stick-mouse quickly change a key measurements from 10 to 12 on the blueprint so that the trap falls two centimetres away from the finish point and return to their original positions before Tom returns to building his own mousetrap.
Split into simpler sentences: The stick-mouse quickly changes a key measurement so that the trap falls two centimetres away from the finish point. They then return to their original positions and Tom returns to building his own mousetrap.