from the beginning of the "knowledge" of the DEO, we have been shown its great chambers that house many known aliens, with the abilities to create or reduce certain atmospheric conditions as needed. however, they just send mon-el away. um.... would it have been too hard to put him in a chamber for a little while, and introduce him little by little over time, to a level of lead so he can get used to it? i mean unless they do have plans of his return somehow in future episodes or alternate series. it became one of those moments that make you wonder, "why did they let me be smarter than the show."
Review of Nevertheless, She Persisted
