Complex sentence: Superman, feeling as if he was being interrogated, refuses to continue the interview and tries to leave, but Sam tells Superman that if he leaves he'll be declared an enemy; he leaves anyway, and Sam orders the Army to attack.
Split into simpler sentences: Superman, feeling as if he is being interrogated, and tries to leave, but Sam tells Superman that if he leaves he'll be declared an enemy. Superman leaves anyway, and Sam orders the Army to attack.