when I am reviewing an answer, I only see the answer to be reviewed and the corresponding question.
If the answer actually answers the question - at least to some extent - then I have to look at other answers to see if it is not a duplicate. This is sometimes problematic, especially when using a smartphone...
For convenience, I would suggest one of the following:
Show all the answers in review mode,
Introduce a "show other answers" button,
Show at least accepted answer - if any.
(The last option would not quite solve the problem, though)