两一 is not a real Chinese word - it shows up in subtitle corpora as a tokenization artifact where
两 ('two', used before measure words) and
一 ('one', often opening the next phrase) end up adjacent. If you see it in writing, look on either side: it usually parses as the tail of one phrase followed by
一 plus a measure word. Real word for 'two' before a measure word is just
两 (e.g.
两个,
两本); real expression for 'a couple of' is
两三 ('two or three').
