How beneficial is the co-op for PhD-MD programs?

I recently attended Drexel’s accepted students days, and it really got me thinking. I know I want to be a doctor, but research seems so alluring to me. I don’t have enough experience to really decide my future, but I want to keep my options open. At Drexel, there’s a wonderful co-op where I could build my resume with in-depth research in case I chose to pursue an PhD. Research would also bolster my MD application. The speaker at Drexel mentioned that since a co-op is longer than just a summer internship, one would learn more, gain more experience, and develop stronger bonds with the mentors. If you know about MD-PhD programs, or just PhD or MD programs in general, would a co-op be better than just summer internships? Would it be worth going to Drexel over UPitt or Boston University? Thank you for any input!!!

Made a few typos