That was a little weird. I am pretty sure that after the sarcastic clap Ferdinand went back to him and shook his hand. I think it might have been to try and avoid retroactive punishment? Or maybe he just regretted it in the heat of the moment but it was pretty odd.
Meh, you see it quite often, huge reaction, going and complaining, then players walk off start shaking hands and come back to shake the officials hands, its always quite odd.
In terms of the performance I think Utd actually started to withdraw backwards after the goal, before the sending off, and that Real had changed from a sit back and try and nab a late goal if needed, to a more proactive gameplan. The biggest shift in the game happened with Utd's goal, not the sending off, the sending off just made it harder when Real got ahead, for Utd to make a better go of it when they had to push forwards again.
Exactly as happened with the Utd goal, happened again with Real's second, Real started to hang back, not push, not over commit and Utd suddenly went from hanging on to have to get a goal.
The simple fact that Utd managed to push forwards when they went behind proves that Nani wasn't what changed the way they played or prevented them pushing fowards.
Nani's to blame for a reckless tackle, but Fergie is to blame for the tactics. Sitting back against Real is asking for trouble, and they got it. When they pressed Real, they isolated the front guys and the movement from Ozil, Di Maria while he was on, Khedira was awful, Khedira kept electing to go backwards, they just werent' clicking, they've been like that all season. When Utd backed off, they let the midfield get forwards, the fullbacks push on, and the front three got closer and everyones passing improved.
They simply shouldn't have backed off after the goal, full stop, they invited pressure and Nani's sending off may well not have happened if they'd kept Real pinned back and their forwards all isolated.