Unexpected hero

1234567
Across
  1. 3. remove (someone) from active service in the armed forces because of injury or illness.
  2. 5. a person who betrays someone or something.
  3. 7. compulsory enlistment
Down
  1. 1. silly or high-spirited behaviour; mischief.
  2. 2. make (someone) annoyed or irritated.
  3. 4. dislike intensely.
  4. 6. a sort of dry humour.