Clemenza took part in the killings because Michael trusted him, and because he was showing loyalty. I don't think Tessio was reaching for a gun--it was just a gesture. He knew it was all over the moment Tom said, "I can't come either," and all those guys surrounded him.
Ntra la porta tua lu sangu � sparsu, E nun me mporta si ce muoru accisu... E s'iddu muoru e vaju mparadisu Si nun ce truovo a ttia, mancu ce trasu.