I guess they'd have pee breaks every six hours or so.
As for this:
"This series could go 15 years," he says. "This could be Law & Order. If we do the CTU thing for seven years and then want to do a day in the life of a cop with a different actor, we can."
I really think they've missed the boat here. If they hadn't gone back to CTU for season two, but instead gone someplace completely different -- as I believe they'd talked about at the time* -- they might have gotten away with it. But now they're pretty married to the CTU concept. The series wouldn't survive without CTU, and probably wouldn't survive without Jack.
* For instance, Year Two might have been opening night of a play. Year Three might have been about stockbrokers.
There was even some talk, I think, of using the same basic cast of actors playing roughly the same characters in a new 24-hour situation every year. So Jack would always be a hard-ass get-it-done sort of guy, and Tony would be his somewhat embittered loyal sidekick, and Palmer would be the conflicted but essentially virtuous leader -- but one year they'd be chefs, and the next they'd be public school teachers, and so on.
If I'm remembering right. Regardless, they stopped talking about this very quickly.