CHICAGO (CBS) — Officer Jason Van Dyke testified in court Tuesday, taking the stand in his own defense. He claimed he just wanted Laquan McDonald to drop his knife.

Van Dyke said he fired his gun due to fear. CBS 2’s Roseanne Tellez reports Van Dyke took the stand, showing a gaunt of emotions. He teared up, but also showed frustration by the prosecutors’ cross examination, repeatedly saying: “Miss, let me answer the question,” and “Miss, you’re putting words in my mouth.”

Jurors listened as Van Dyke testified in his own words, explaining that he has had to draw his gun probably more than 20 times in his career.

“Did you ever have to fire your weapon?” asked prosecutors.

“No and I’m really proud of that,” said Van Dyke, explaining that he never fired his weapon until October 2014 when Laquan McDonald advanced toward him.

“He had no expression. His eyes were bugging out of his head. He had huge, wide eyes,” Van Dyke said, claiming their eyes locked and McDonald never stopped advancing and ignoring orders to drop his knife.

“He waved the knife from his lower right side upwards across his body toward my left shoulder,” Van Dyke testified. When asked what he did next, Van Dyke responded, “I shot him.”

Under cross-examination, Van Dyke went from soft spoken and at times emotional to becoming frustrated.

“Do you see that in the video at all, Laquan raising the knife?” prosecutors questioned.

Prosecutor Jody Gleason replayed an animation defense attorneys said showed Van Dyke’s point of view.

“No, it’s not my perspective. It shows the back of my head and not from my eye-level and not showing what I saw,” Van Dyke stated.

The defense is expected to rest the case Wednesday when rebuttal witnesses will be called.

Closing arguments are expected Thursday or Friday.