A surgical device mitigates over-puncture with a bias spring that biases a leading, cutting edge in the opposite direction of the anticipated over-puncture. An associated locking mechanism is configured to release the force of the bias spring in a direction counter to the direction of insertion when the tension force of tissue against the cutting edge is released. Thus, when an opening in the tissue forms, the tension is released and the cutting edge can move opposite to the direction of insertion of the surgical device at the same time that an applied force drives the instrument in the direction of insertion. In this manner, the spring and locking mechanism cooperate to move the cutting edge opposite to the direction of insertion as soon as an incision is made.