Shadowed a doctor

Hi! I'm a rising senior. I shadowed an OBGYN for 40+ hours last summer and am shadowing an oncologist for 80+ hours this summer. I'll be applying for cell and mol bio on the pre-med track. I was wondering whether I should ask the oncologist for a recommendation letter. I'll be submitting 2 teacher recommendations (and maybe another one from the school 'counselor') and 1 from my research internship program's director. Would adding another rec letter from the doctor be too much?