Sorry, completely missed the context of “person quits” because, for me as for you, that is extremely incompatible with “must be escorted out of the office ASAP”.
And, by the way, “leaves angrily, and may steal or destroy company property“ isn’t the only, and sometimes not even a reason for getting people out of the office as soon as possible after firing them. Certainly during mass firings, it also is about morale for those who are allowed to stay.
It’s no fun hearing that, from now on, you’ll have to do with 20% less head count for the same amount of work, but it’s even less fun when there are people sitting around for a few weeks who say “it’s not my problem. I’m fired”.