I'm a fairly advanced learner trying out the Rosetta Stone free trial. I'm trying out the emergency situations lesson, and they teach "the person is choking" to you as "se está ahogando." Somehow, this sounds strange to me. My gut reaction was "shouldn't it be 'está ahogandose'"? But I wanted to come here to clarify. Would the latter be used to mean "they are CHOKING THEMSELF" vs the former meaning "They are choking"? Or is there really not much of a difference and it's about personal preference?
It just sorta seemed strange to me that "se" preceded "esta" in that sentence.