We can kill her, but will lose in a straight up fight.
IIRC Oero is weak to sneak attacks, as evidenced by how UMP dealt with her. Second her armaments while powerful are designed primarily as a standoff long range weapon.
She cannot use missiles at close range, especially not CQB, and her guns (also mounted in the floating pods) could theoretically target V but wont shoot if shes in Oeros face due to her own self preservation instincts.
Her frame is also week compared to other ringleaders, specializing in command/support, and not direct action- that's her own pride leading her into a disadvantageous position.
Also the fact those gun/missile pods are floating gives V an advantage. Since they are on both sides of Oero, she has a high chance to simply grab hold of one and either redirect it at the other one, or use its own momentum to redirect V in a safe way to behind them as Oero tries to target her once the trap is sprung- giving V extra time to get behind Oero, instead of in her face.
Likewise, the same rules apply if the ambush fails she can evade gun fire, and being surrounded by buildings Oero will likely not fire missiles for fear of being disabled or buried under debris.
It's very situational, but if it fails, we still get a backup plan, and Oero is likely to bite since V snarked at her some time ago.
