Usually he just gets off without doing anything? That's not cool, we can't get off then.
So good thing we got to see the time when he did actually have sex with her.
Also, how lucky that nobody wanted to use the elevator when they were having sex. Maybe it's just a common courtesy thing where there's an alert that sex is happening and they patiently wait for it to be over first. People in Hentai can be so nice.
Should come with a disclaimer to be "vewy vewy" careful about trying this in real life, as most elevator cars contain a camera viewing the interior for security purposes. Then again, IF the parties involved are O.K. with that, who am I to discourage them?