Long lunch?

Today my manager called me and a co-worker into one of our conference rooms and proceeded to yell at us for taking too long of a lunch the day before. According to him, we had been out of the office for "over 90 minutes" and that his manager had found the lab completely empty at 2:00 P.M. and had raised a stink with him. He made it clear that we weren't to take "long" lunches and that we were to be back in the lab every day at 2:00 P.M. There was no discussion of how many hours each of us put in every day during this busy period.