ʿIrāk and tahaddud are related but not interchangeable. The first is the physical or social clash itself; the second is the menace and pressure of intimidation.
TermCore meaning
عِرَاكCollision, fighting or struggle
التَّهَدُّدThreat, intimidation
حِفَاظًاFor the purpose of protection
The contrast makes the poet's claim more precise: he faces danger while refusing to surrender to fear.