He didn't go into it "straight from Avengers" he actually filmed this over a two week period while still filming "Avengers" as was originally reported when news of this first came out in the summer time.
Not according to IMDb or any other sources I've encountered, which agree that it shot after principal photography on the Avengers movie had ended.
Yeah, it was a twelve-day period (a week off from Marvel, plus two weekends) after principal photography wrapped on Avengers
but prior to post-production. So, Much Ado
was put together while work on Avengers
was underway but after filming had stopped.