It's because they're still in the bathroom, where they've been hiding since 3 PM.
Apparently, they were feeling a bit "uncomfortable" with the meeting's discussion on "The Future of Toilet Paper in the Workplace".
Or maybe they just really needed to use the "Executive Bathroom" which is only accessible via a secret button that only we know about.
Anyway, we're still waiting for them to show up, and we're starting to get a little "flush" with anxiety.
Why Not 1/3? Maybe They're on a Coffee Break Why Not 1/4? They're in the Conference Room... with the Coffee Machine Why Not 1/5? They're on a "Personal Emergency" Leave of Absence