Complex sentence: To preserve both security and ability to complete their missions, officers as well as enlisted men go through rigorous survival training (SERE) so they are able to make the right decisions under unpredicable and difficult circumstances.
Split into simpler sentences: To preserve both security and ability to complete their missions, officers as well as enlisted men go through rigorous survival training (SERE). This, to be able to make the right decision under unpredicable and difficult circumstances.