Engineer with a low BCPM - should I retake classes?

I graduated with a Bachelor’s in 2016 and a Master’s in 2017 both in Biomedical Engineering. Currently, I work full time in the medical device industry as a development engineer working on a cardiovascular device and I am planning on applying to medical school for the 2021 cycle. I originally planned on pursuing medical school the year after my Master’s, but a move away from home and adjusting to working full time caused me to get temporarily side-tracked. I also wasn’t premed for a majority of college, but began taking the remaining pre-requisites my Junior year once I began seriously considering medicine as a career. Due to this, I felt very behind the experience level of traditional premed students. Many of the pre-requisites were required by my major and I took them early on in college, before I had properly learned to study. I graduated with a 3.7 from undergrad and a 4.0 from grad school. However, my science GPA is only a 3.4 since a majority of my classes in undergrad were BME and therefore it doesn’t seem as if they’ll count towards my BCPM (although many were heavily science based including courses such as Human Physiology and Thermodynamics). Included in this average is a C+ in Physics I, B- in Physics II, B- in Organic II, and a C- in Calculus II. The rest of my science grades are mostly A’s (Including Orgo I and Biochem) and a B+. I also had straight A’s my junior and senior year (mostly engineering and biology coursework) including upper level physics based engineering courses while taking over 18 credits a semester. My question is, should I consider retaking courses such as Physics I & II to show a higher level of competency or will my upper level engineering courses be considered and help to compensate? I plan on taking courses at night at a local university this year to obtain recent letters of recommendation, however I was leaning towards taking a Pyschology course (since I only have an AP Pysch (5) transfer credit and a Medical Anthropology on my record for the social sciences), a Biology course with a lab (since I transferred a 5 in AP Biology and none of my upper level Biology courses included a lab), and an Inorganic Chemistry course (since I only have one semester of Intro Chem w/ lab). I am trying to save money where possible, but I’m willing to do what it takes to ensure I can show I am ready for medical school. Should I also consider a post bac program so that my grades are more recent since I will be applying four years out of under grad? Also - I am planning on taking the MCAT for the first time this coming fall so I don’t have a score to share yet.

On the experience side, I have shadowed over 200 hours of orthopedic surgery (trauma, spine, joint replacement, pediatric, etc.) and neurosurgery during graduate school. I plan on shadowing several more specialities before applying, hopefully including emergency medicine and primary care (aiming for 30-50 hours in various specialties). I was actively involved in professional societies in undergrad that included volunteer opportunities and I was the Community Service Coordinator for the Biomedical Engineering Society my senior year. I was a TA for team based engineering classes my sophomore, junior, and senior year of college and in grad school. I also currently organize volunteer activities at work in the nearby community. However, none of the hours were formally tracked and the only consistent volunteer position I had was once a week for four months in an outpatient orthopedic clinic (some patient interaction including transporting patients to the x-ray room). I am actively seeking clinical experience and volunteer experience (ideally weekly). Do you think that adding a variety of shawdowing experience and a weekly clinical experience with patient interaction spanning over the next year will be enough to show how serious I am about wanting to be a physician? I know that my lack a patient centered clinical experience is a major weakness currently. I am also prepared to switch to a clinically related job or work part time to have more time to volunteer and gain clinical experience, although keeping my current job would allow me to save money and I am committed to finishing a project at work for the next few months. I greatly appreciate you taking the time to read this long explanation and thanks in advance for any advice you may be able to offer!