"You know me," Elektra replied, as though that was all there was to it. Boredom, a fight, a recipe for disaster. But Elektra was used to playing fast and loose with her life and didn't see that being anyone's affair but her own. So when the wolves came (and they did) and when the vampires joined them (and they did), she was ready.
For a few long minutes, it was exhilarating. Blood and gore, a bone-white fang knocked out of a wide-open mouth, the tangle of blood-matted fur between her knuckles. She stabbed and swung, carved and killed. And through it all, she was aware of Octane on her periphery, keeping pace. His gun only had so many bullets, though, and those legs of his gave him enough speed to dodge and leap and kick, but left the rest of his body exposed.
Elektra didn't care. Shouldn't have cared. Elektra had resolved herself to not giving a damn one cold night in the hotel kitchen, the fridge door open at her back, but here she was, finishing off the opponents Octane had started on, dodging a few of her own and leaving him to handle the final blow.
It wasn't a matter of trust, but it was something like it. And the whole time, Elektra kept waiting for Octane to stab her in the back.