An apparatus comprises a body, a shaft assembly, an end effector, a cartridge, and a staple driver actuator. The end effector is operable to manipulate tissue. The end effector comprises a lower jaw, a pivotable anvil, and a translating cutter. The translating cutter is operable to translate relative to the lower jaw and the anvil when the anvil is pivoted toward the lower jaw to manipulate tissue. The cartridge is insertable into the lower jaw and includes a plurality of staples. The staple driver actuator is disposed within the cartridge. The staple driver actuator comprises a secondary cutting element. The translating cutter of the end effector is operable to drive the staple driver actuator distally to staple and cut tissue substantially simultaneously.