U.S. Secretary of Defense Lloyd Austin addressed his cancer diagnosis and secret hospitalization in a rare press conference on Thursday at the Pentagon, where he faced an intense grilling by reporters.

“I asked my assistant to call the ambulance. I did not direct him to do anything further than just call the ambulance,” Austin said, referring to a Jan. 1 911 call, the contents of which were first reported by The Daily Beast.

An aide, whose identity is redacted, can be heard in audio of the call asking the dispatchers to have the ambulance arrive at the secretary of defense’s house with no lights and no sirens.

“Can I ask—can the ambulance not show up with lights and sirens? Uhm, we’re trying to remain a little subtle,” the aide said, according to the recording, which The Daily Beast obtained from a FOIA request.

Austin said Thursday he did not handle his hospitalization correctly, and that he wishes to apologize to the American public for concealing his cancer diagnosis. In December, he was diagnosed with prostate cancer and had surgery to treat it. The next month, he went to the hospital due to complications from the procedure. For days, he kept his ailment secret from senior Biden Administration officials, including the president himself.

“We did not handle this right. I did not handle this right. I should have told the president about my cancer diagnosis,” Austin said.

He added that the cancer diagnosis was a shock to him and that his instinct was to keep it private. Austin said he has since apologized directly to the president.

The secrecy surrounding his ailment has stirred controversy in Washington, raising questions on both sides of Pennsylvania Avenue, over when senior leaders in the administration ought to disclose they need to delegate their powers and authorities when they are in crisis. In the days since, the White House has initiated a review of notification guidelines for Cabinet officials who can’t perform their duties. The Pentagon’s inspector general has also established a review.

Austin denied that he has cultivated a culture of secrecy in the Pentagon, adding that he didn’t tell the president in part because he didn’t want to over burden him with everything on his plate already.

“I just didn’t feel that was a thing I should do at the time,” he said, reiterating that he recognizes that was a mistake.