Spoilers for Mr. Robot follow. After her death in the previous episode, you may not have expected Trenton to play such an vital role in "Eps3.7dont-delete-me.ko." But Elliot may be able to undo the Five/Nine hack on Mr. Robot now, thanks to Trenton's ingenuity. Also, Trenton's younger brother unwittingly stops Elliot from killing himself in the episode, so Elliot owes more to his fallen fsociety colleague than she'll ever realize. This could all be an elaborate setup, since a mysterious van returns Elliot's personal items to him at the end of the episode. But it seems like Elliot could reverse his biggest regret by the time Mr. Robot Season 3 is through.
At the end of Season 2, Trenton told Mobley that she discovered something. "We could potentially undo this whole thing, put everything back the way it was," she said. Angela has been fixated on undoing everything, even appearing to believe that she can undo the deaths of her mom and Elliot's dad. But Trenton was just talking about the Five/Nine hack. The fsociety hack was supposed to halt E Corp's spread and make people's lives better, but it has only led to more destruction and terror. So Trenton investigated a potential fix.
When Leon of the Dark Army showed up in Arizona and captured Mobley and Trenton, Mobley thought Trenton had emailed her discovery to the FBI. But instead, she said, "If anything does happen to us, if I don't make it back to my computer, I sent the email to go out automatically to someone I trust." And her instinct was right since the Dark Army killed her and Mobley shortly after.
Somewhat surprisingly though, the person that Trenton trusted turned out to be Elliot. He was intent on killing himself during "Eps3.7dont-delete-me.ko," but the universe (or, perhaps, some other entity) had other plans for him. He wipes his computer clean and destroys his personal items at the beginning of the episode. But by the end, he has purpose again. Because when Elliot sets up a new computer, he finds an email from Trenton with the subject line, "Don't delete me." Within it, he finds the following message:
"I may have found a way to undo the hack. I've been investigating Romero. He installed the hardware keyloggers on all the machines at the arcade some time before five/nine. The NYPD imaged all of his data after he was murdered. I was able to get this chain of custody document from the NYPD when they prepared to transfer the evidence to the FBI. They couldn't get into the encrypted keylogger containers. If Romero somehow got a hold of the keys, or even the seed data and source code for the encryption tools, the answer might be in those keylogger captures, but the FBI probably has those files now."
The cybersecurity company Kaspersky Lab noted in an article that keyloggers "secretly monitor and log all keystrokes." But even without understanding hacker speak, the point is that Romero (Ron Cephas Jones, who has been busy on Luke Cage and This Is Us since his character's death) may be the (ahem) key to undoing the hack. If Elliot can get these files from the FBI, then he can see how the hack was done — since he was under the influence of Mr. Robot at the time and doesn't remember — and possibly retrace his steps to fix it. And based on a Season 3 trailer released on Oct. 7, it looks like Elliot is going to succeed.
Now, if you've been a fan of the Season 3 time travel theories, this might be a bummer. Like Angela, you may want more of the past erased than just the hack. Yet, time manipulation may not be off the table completely. Back To The Future II, which has played a part in fueling the time travel idea, is prominently featured in "Eps3.7dont-delete-me.ko." And the song at the end of the episode — "In Time" by Robbie Robb — is from another '80s time traveling movie, Bill & Ted's Excellent Adventure.
These pop culture references could be Mr. Robot creator Sam Esmail trolling viewers. After all, Esmail could have intentionally misled fans throughout Season 3 with the knowledge that they'd start to consider a time traveling twist. But how did Elliot get all of his personal belongings back at the end of the episode? Is it possible that the Dark Army wants Elliot to discover how to undo the hack? After all, E Coin has made it so E Corp is still flourishing, so perhaps the hack must be undone in order to really defeat the corporation. And maybe after the hack is fixed, the Dark Army will enact its own program to change the past even beyond that point.
Right now, the Dark Army's intentions are still unknown, but Elliot is reinvigorated because of Trenton's final act. So expect him to hack the FBI — or (it's a long shot) possibly work with Dom at the FBI — to undo the very same hack that he had orchestrated in the first place. That means Mr. Robot might be going back in time one way or another after all.