If the play actually ended up being meaningful, the refs would have been more careful about what they called. I'm sure they were ready to get off the field and out of the line of fire.
Having somebody on the field on an extended play that goes sideline to sideline a couple of times would be easy to call interference. And Utah would be in the position of trying to argue that their Athletic Director who came on the field to yell at the officials during a play didn't actually interfere with the play.