Getting into a Bioethics/Philosophy Master's Program
There are a couple of tricks to getting good LORs.


You can ask more than one person, you know.
Approach the person and ask (by email if you like) whether s/he would feel comfortable writing you a LOR.  If s/he thinks the letter would come out lukewarm, s/he can say something tactful, such as "I think you would do better to ask someone who ... (e.g. knows your work better than I do)
Send the person an unofficial transcript
Give the person an outline of what aspects of you should be emphasized for the particular application


I think the Caribbean is fine; also a reference from your workplace is fine.  Do supplement it with a purely academic one.