WARNING: The following contains spoilers for Daredevil #26 by Chip Zdarsky, Marco Checchetto, Mike Hawthorne, Adriano Di Benedetto, Marco Menyz & VC's Clayton Cowles, on sale now.
Daredevil is in prison, trying to atone for what he believes to be his failures. And with Matt Murdock is behind bars, Elektra has taken over as the resident guardian of Hell's Kitchen, and she's adjusting to her new role by holding back on her more lethal impulses.
When Elektra first appears in Daredevil #26, she's dressed up in her Daredevil costume and hangs a gunrunner over the ledge of a building, where she's threatening his life. That's where the entire problem in Elektra's mind started. She admitted to herself that she wouldn't kill him, although she felt she needed to kill him and she wanted to kill him. However, she won't cross that line out of respect for Matt Murdock.
Elektra wants to protect Hell's Kitchen while Daredevil is in prison. She feels that Hell's Kitchen doesn't need Elektra protecting it. The city needs Daredevil, so she took on the role of the vigilante hero. She promised Matt Murdock that she would not kill people while she was on the streets protecting citizens from bad guys. She kept her word here, letting the gunrunner live and ordering him to leave Hell's Kitchen and not to return. While she promised Daredevil she wouldn't kill, there is a chance that if this guy showed up again selling guns to people, she might go back on that promise.
But for now, she seems intent on keeping her word to Matt and going against her every instinct. As she said in this issue, she has no idea what Daredevil will ever hope to accomplish by fighting crime with a non-lethal mindset. If she took the gunrunner to the police, Elektra knows it wouldn't matter because that is just another corrupt system.
Elektra came into the story so many years ago as part of that corrupt mindset. She knows that Wilson Fisk is the Mayor of Hell's Kitchen, and as long as he is in charge, nothing will change with the law enforcement protecting Hell's Kitchen. They are there to serve Fisk's wishes and only work to ensure that his version of Hell's Kitchen remains intact. That code is against vigilantes like Daredevil and only cares about protecting the villains Daredevil wants to stop. This is even more true because of what Elektra really wants deep down.
Before Daredevil turned himself over to the police and allowed himself to go to jail, Elektra was able to embezzle millions of dollars that she planned to use in her war with The Hand. However, even in that situation, Daredevil used his kindness and goodness to convince her to donate that money in buying back Hell's Kitchen and helping the people on the streets. With that said, Elektra is working as Daredevil to convince Matt that she is willing to follow his lead and make sure the streets remain safe while he sits locked away for the sins of his mind. If this can convince Daredevil to join her to use the Fist to bring down the Hand by her side, she will continue to curb her own instincts and not kill the criminals that she so wishes that she could.