I have observed this procedure, but not actively participated in it since the first working group meeting a few months ago. At that time it felt pretty comfortable and the Yes vote was in reach.
When this day approached both camps, the pro Office Open XML team and the no-sayers both gathered their forces for the final battle. We all entered the meeting at the last possible minute and we all was signed in to the meeting.
Starting with IBM, a number of representatives ran out of the conference room mumbling and cursing when they realised in which direction the vote would go - and the vote result was clear to most of us. After a presentation round and a round of all members commenting their voting intentions, we all thought that it would be a quick vote.
The representative from IllumiNet, flanked with Sun and Google, did try to convince all the yes-sayers for a long time and the discussion went pretty harsh! I have to give credit to the guy, who fought for his cause and really had put some time into the specification. Finally someone asked him "if ODF was up for voting, would you let it pass through"? After some thinking he answered "No, I would not!". This ended the discussion.
The vote went quick and it was
26 25 votes for yes and 6 for no. Read the press release from SIS here (in swedish).
Now we all have to wait and see what will happen on september the 2nd when the global vote will take place...
UPDATE: Correct amount of yes votes is 25. 26 was taken from my head when writing this one and 25 is according to my meeting notes.