While working in the White House Situation Room, Mike Stiegler was also earning his Master of Liberal Arts (ALM) in the field of International Relations. Recently, he spoke with George Stephanopoulos for his new book, The Situation Room, about the events that unfolded in the Situation Room on January 6, 2021.

The full transcript of their Good Morning America interview is below.

Robin Roberts: Welcome back for more of our ABC News exclusive: Inside the White House Situation Room. And you sat down with the gentleman who was on duty on October 6.

George Stephanopoulos: On January 6.

RR: January 6, excuse me.

GS: Mike Stiegler is an amazing man. He’s a true patriot, quiet man, committed, super competent. He always wanted to work in the Situation Room but never imagined he be there helping hold the government together on January 6.

GS (voiceover): For Mike Stiegler, working in the White House Situation Room was a bucket list dream come true. A duty officer, he served from 2019 to 2021 under both the Trump and Biden administrations.

GS: What exactly is that work on any given day?

Mike Stiegler: Sifting through different intelligence, and we’re providing those updates to the president’s national security adviser, the vice president, and all their staff.

GS: You know, you light up when you talk about the Situation Room. What stands out from your time in the White House?

MS: The biggest thing that stands out to me is my colleagues.

GS: And at the core of this — apolitical?

MS: Apolitical.

GS: What does that mean to you?

MS: That I am there to execute my responsibilities without question and without allowing outside influence to come in. You are to execute, regardless of your own opinions and the opinions of others.

GS: How do you balance serving the president and serving the presidency?

MS: I knew that going into this, right? I had talked to a lot of friends who had served in previous administrations before I took the assignment and they said, “Look, it’s going to be a little different this time around because there’s going to be more pressure to act for the president and not the presidency. So if you go into the mindset that I’m there to serve the presidency, I’m there to serve the executive branch, regardless of what goes on. It puts you in a better mindset.”

GS: I want to talk about January 6 — you were the duty officer that day.

MS: Correct.

GS (voiceover): On the morning of January 6, 2021. Stiegler headed to the White House to start his usual 5 a.m. shift. Later that day, the riot erupted at the Capitol.

GS: At what point did you know that the Capitol had been breached?

MS: As soon as it was called out on the radio. But we thought somebody breached the gate and or somebody breached a barrier. So when they called out that the Capitol was breached, we, at first we didn’t know what that meant. At the time, too, the vice president was there and one of the responsibilities of the Situation Room was to always maintain communication with the president and the vice president.

So those were the initial conversations of, okay, where is he? How can we locate him? You know, how do we maintain that communication?

GS: You told me, people didn’t understand how close we came to losing the vice president. What’s going through your mind when you are hearing that the vice president’s life may be in danger?

MS: We started having the conversations, “Okay, if VP’s down, what’s next? What do we got to do? How do we how do we keep moving? Where’s where’s the third– the second in line.

GS: Kind of remarkable in you know, what you’re describing there is that you started to implement and go through the checklist that–

MS: The Situation Room did yeah.

GS: The Situation Room.

MS: Correct.

GS: Of what is called the continuity of government procedures.

MS: Yeah.

GS: Describe what those are.

MS: Those are originally instituted for if there’s an attack on the US government, how does the government — especially the executive branch — keep going. So that means line of secession. That means how do we move to different locations and how do we keep the government going.

GS: During a riot of our own people?

MS: Yeah.

GS: Inspired by the man sitting upstairs.

MS: Correct. But at the time, that’s not even in the forefront of our minds. It doesn’t matter how we got here. We’re here. How do we execute? How do we move forward?

GS: Did the president ever call down to the Situation Room on that day?

MS: Not to my knowledge.

GS: Not once?

MS: No, sir.

GS: Didn’t ask what was going on?

MS: Not to my knowledge.

GS: Didn’t ask how the vice president’s doing?

MS: Not to my knowledge.

GS: Some people even questioned– elected officials, whether the vice president was really in danger. You see a lot of revisionist history going on about January 6. As someone who is inside the room that day, what’s your reaction?

MS: It’s important to me that we don’t forget that it did come that close and that we did have discussions if we lose the VP, if the 25th is invoked. We started running through all of these game plans because it was getting close.

GS: 25th amendment.

MS: Correct.

GS: How did you all talk about it afterwards?

MS: There’s some of us that won’t talk about it. There’s a handful of us that we still talk, and every January 6, we get together, and we have a toast. We go to the Lincoln Memorial, and we just have that toast and we don’t really say anything.

GS: But what is it a toast to? Surviving? Getting through it?

MS: The day after, so January 7, I was back at it. Back at 5 a.m. And a frequent visitor of the Situation Room under the Trump administration was Lieutenant General Keith Kellogg, the vice president’s national security adviser. You know he would come by and just get a general feel of how the day is starting. And at the end, I turn and look at him and I go, “Sir, how are you doing today?” And he takes a deep breath. And he taps the table twice. And he looks at me and he goes, “The Republic still stands.” But I think that that’s what it’s a toast to, that the Republic still stands.

GS: Incredible man, such an impressive man. It was not easy to convince Michael Stiegler to speak about that day because it’s still so painful to him. But I was very gratified because I heard from him earlier this morning. And he said since his story has started to come out, he’s heard from many of his other colleagues who said now they feel free to absorb the experience again and talk about it. It was so traumatic for so many of them who work inside.

Lara Spencer: And for so many of us watching. It was just shocking.

Robin Roberts: Why did you want to write the book and what do you hope the reader takes away?

GS: Well, what I hope the most is that people get to meet people like– that everybody reading gets to me people like Mike Stiegler. This– the Situation Room over the last 12 presidents has been populated by people from all across the government who are out there to serve their country on the front lines every single day, and they’re all impressive.