Hi Sam, Yes, medical officers can do the AACC. Most docs who want to go down the route of doing an arduous course (AACC or P company) will try and get it done during their GDMO years (the 3 years between FY2 and starting specialty training). If you let it be known early that that is what you want to do and you have the support of your chain of command (they won't support someone who they don't think could be successful) it usually works out ok. Saying that, sometimes the needs of the Army come first, and if it's a particularly busy few years, you might be needed elsewhere. I wasn't sure about serving in the marines so I asked a navy colleague for help with that question! As a GDMO you won't be attached to a marines unit, they tend to only use navy GDMOs. However, you could be trawled to deploy or go on exercise with the marines. I covered a joint army/marine jungle training exercise and I have colleagues who deployed on operations as a GDMO with the marines and colleagues who have provided med cover for some of their winter training exercises as well. You can apparently be attached to the marines as an RMO (a GP) as some (but not all) of their jobs are open to both Navy and Army docs.