if / unless / unless otherwise

English as a Second Language English Vocabulary, Grammar and Idioms
1
  1. He threatened that he would shoot me if I didn’t obey his instructions.
  2. He threatened that he would shoot me unless I obey his instructions.
  3. He threatened that he would shoot me unless otherwise I obey his instructions.
    Please correct all.
    Thanks.
2
  1. obeyed (past tense, as the threat is in the past.
  2. is incorrect in its use of ‘otherwise’…
    He said I should obey his instructions, otherwise he would shoot me.