Some options for "(verb) to embark, set off" could include:
1) bosulif (root words are bo - su - lif) or (fly air leave)
2) gonaasah (root words are gonaas - amativ) or (commence forth)
3) gonlifbo (root words are gonaas - lif - bos) or (commence leave fly)
Relating embak to somthing like gonaas (commence) and/or bos (air) and or lif (leave) could work well for this word.