UMD self is a reasonable good univ with the good reputation med school. Mostly important, both NIH and JHU are around there, leading to great opportunities for hypothesis driven biomedical research that is very important to get in an MSTP program, especially the top MSTP programs.
The NIH funded MSTP program is aimed to train next generation of physician scientists. The MSTP journey is long and tough. Especially, you make money at least 4 yrs later compared to your MD only peers. However, this is a great career path to someone who loves sciences and sees patients.
As usual MD only applicants, you have to have sGPA and MCAT >= average in a specific medical school. 3.9+ plus 520+ from UMD should be good enough for T30 MSTP programs , the achievements of research, the letters of recommendation from research mentors, the passions for sciences and the communication and writing skills will be decision-making factors. If aimed at top 10 MSTP programs, the strong leadership is a must.
GL