Is it common to not put article on "campus"?
"Campus" may or may not have an article in front of it, depending on the context it is used in. It is common not to use an article before "campus" when it is already known which campus you are talking about. In this case, the campus isn't known, however, he omits the article "the" here because "the" is already implied. It is common to omit "the" before "campus" to sound a little more casual. Ex: I'll be on campus at 10am. Ex: We toured the campus and then were given a meal. In the first example, there is no article in front of "campus" because the speaker is talking to someone who already knows which campus they are going to. In the second example, "the" is used to specify which campus, however it can be omitted to make it sound more informal.