In more than six hours of historic testimony Wednesday, former special counsel Robert Mueller issued a warning that Russian election interference remains a threat, and he emphasized that his two-year investigation did not exonerate the president. But mostly, he stuck to the script. Many considered Mueller a reluctant witness, and he offered one-word answers more than 170 times.

Former FBI Deputy Director Andrew McCabe was fired by President Trump in 2018 and has been outspoken in his criticism of the president since. After the hearings concluded, CBS News' Paula Reid asked McCabe, who served as deputy director at a critical time during the Mueller investigation, about Mueller's performance, concerns about his demeanor, and whether he was surprised that Mueller said investigations related to Russian interference are still open.

Below are excerpts from that interview:

On Mueller's performance: "It was an incredibly cautious appearance"

ANDREW MCCABE: You know, I think he did exactly as I and many other people expected. He was pretty clear going into this hearing that he was going to do everything possible to stay within the four corners of the report. And I think he did that effectively. I thought it was an incredibly cautious appearance for the director which, again, is what we expected. You know, there was a lot made today of the fact that this was his 90th appearance on the Hill. One thing I think is helpful to remember, that this is probably the first appearance he's ever done that was preceded by a 400-page statement. So I think the Bob Mueller we saw today was doing everything possible to preserve the phrasing and the terminology from the report, so he was very reluctant to go beyond that and kind of would only agree to things that were exact quotes.

Did Mueller get his point across about the threat of ongoing Russian interference? "I hope people got that message loud and clear"

MCCABE: It was clear to me from reading the report, from listening to his first public statement about it from the Justice Department, and then of course in the testimony today, that that seems to me like the part of the investigation that Special Counsel Mueller feels most strongly about. That is the enduring threat to our nation, to the foundations of our Democratic process. He said clearly today that that threat continues and he expects the Russians to come at us again in 2020. So I hope people got that message loud and clear, both inside the administration and quite frankly across the country.

On speculation Mueller didn't seem himself: "He's a careful guy by nature"

MCCABE: It wasn't my impression that he wasn't himself. Again, I think he was clearly trying to be as careful as he possibly can. He's a careful guy by nature to begin with. I think he was very cognizant of the limits that had been placed upon him by the Justice Department with that letter he received the night before last. And of course, those limits he placed upon himself. It's also worth mentioning that he clearly went to great lengths to kind of not lend aid or support to either side, and to play it as far down the middle as he possibly could, and to not extrapolate and go beyond the report for the Democrats or the Republicans. So when you add all those kind of self-limiting factors together, you get a very narrow kind of focused response and that's what he delivered today. It's a 400-page report. There were — I've read it a couple of times, and there were a few questions in there that I would not have been able to answer off the top of my head either. I'm sure Director Mueller spent a lot of time preparing, but again, rather than risk getting out in front of the report and saying something that might deviate, even in a minor way, from the phrasing in the report, I think he tried to err on the side of caution.

McCabe "surprised" Mueller said counterintelligence probe continues today

MCCABE: I was surprised that he said it. It doesn't surprise me that they're continuing their work. I was surprised that he revealed the fact that there was a significant element from the counterintelligence division at FBI who were essentially embedded with the special counsel team and there for the purpose of exchanging counterintelligence information in both directions through the pendency of their investigation. And it certainly makes sense that that team would continue to investigate any lingering counterintelligence concerns around the president or anyone in his administration. So I'm not surprised that they're doing that, but I thought it was a pretty interesting reveal on the part of the director.

But the true purpose of a counterintelligence investigation is to mitigate a threat to national security, and depending on the circumstances of the case, that could mean many different things. It could mean maintaining some level of, of a intelligence collection or access to informants or just seeing how a threat that you perceive may exist, seeing how that develops as time goes on.

On Trump's declaration of victory: "I don't know how he derives that message"

MCCABE: You know, it's amazing to me that on a day when a former [FBI] Director, Robert Mueller, Special Counsel Mueller sits in front of Congress and outlines the details of a pervasive and systematic attack by our most significant adversary on the very foundations of our democracy, and somehow the president doesn't even mention that threat in his comments and can refer to today only as, you know, I quote, 'a great day for me.' I don't know how he derives that message from what we all heard today, but I'm not surprised that he's somewhat disconnected from the facts.