The part where he accidentally signed something reminds me of an incident years ago where some random guy pretended to be the sign interpreter for like President Obama or something and he just went up on stage, completely unvetted, because people thought he was supposed to be there and the entire time he was on stage with the President he was just pretending to sign. Deaf people that could sign started going, "WTF?" and eventually it was realized (after the fact) that the guy just waltzed in and claimed to be the sign interpreter. (I looked it up and it was in 2013 while President Obama was giving a eulogy for Nelson Mandela.)
Hilariously, he did manage to accidentally sign a legitimate thing: "Help me."