Do you know anyone on those services or worked with them already? Have you rotated in either specialty yet?
Can't speak to transplant medicine but it sounds like a great opportunity. So does the CT job especially if you are interested in surgery although critical care here will be focused on cardiac; you will also see some Pulm, kidney, and neuro pathology. Some CT surgeons can have challenging personalities so keep that in mind if you haven't worked with those folks yet. I would say take the job that is a better first job for you that will provide mentorship and plenty of learning opportunities.
Anecdotally, I was able to transition from ortho trauma to CT to trauma/surgical critical care. So know that things are possible with the right effort, network, and opportunities.