An apparatus for operating on tissue includes an end effector having a first jaw, a second jaw, a first blade, and a second blade. The second jaw pivots relative to the first jaw from an open position to a closed position. The first blade moves from a proximal position to a distal position to pivot the second jaw to the closed position. The second blade moves from a proximal position to a distal position when the second jaw is in the open position. The second blade is exposed between the first and second jaws when the second blade is in the distal position.