I am a practicing behavioral scientist, my qualifying exams were in psych, and years ago I wrote a dissertation in clinical health psy. I even taught psy related classes before in both undergrad and grad levels. But guess what, I only got 128 in PS. What I want to say is, take the Intro Psy class to know the field of PSY. We design the Intro Psy class to introduce students to the fields of psy - it is an overview/preview of the work we do on our daily basis. Yes, it may help you do well in MCAT, but may not necessary so. But no matter what, it is always fun to know what other people are doing, right? Good luck!