Tonight "Arrow" picked up right where "Dangerous Liaisons" left off -- with Oliver and Felicity stranded inside the Arrow bunker with no way out. The episode, titled "Underneath," was practically a bottle episode that took place almost entirely inside the Arrow cave. Racing against the clock of injury and no oxygen, Oliver and Felicity had to find their way out before the bunker exploded. Diggle had to call on Lyla for help this week, which forced them to continue their dialogue about Lyla operating in the morally gray areas for A.R.G.U.S. With Oliver injured and Felicity's legs not working, they both had moments to confess to one another secrets they had been hiding. The episode was cathartic for any fans who enjoyed Oliver and Felicity as a couple, especially since the flashbacks this week featured an intimate one night they shared together in the Arrow bunker a few months previously. The episode ended with Prometheus tracking down someone very important to Oliver, someone whom may break Oliver and help Prometheus win once and for all.

Learning to Work in Gray Areas

Team Arrow

Tonight's episode of "Arrow" was a refreshing change of pace. It didn't take place completely in the dark, the team wasn't suited up tracking down bad guys in back alleys, it didn't even have a main villain until the very end. The villain this week was not a person but a problem. The problem of finding a way into or out of a bunker designed to withstand a nuclear blast. While Oliver and Felicity tried to find a way out, Team Arrow tried to find a way in. Together Rene, Dinah, Lyla, Diggle, and Curis troubleshot the doors, the elevator shafts, the power supply -- they tried everything they could to rescue their teammates.

These moments of teamwork allowed for each member of the team to shine. Dinah was the motivator, Curtis was the tech, Rene was the mechanic, Diggle was the leader and Lyla was the materials support. This synergy of working together forced Lyla and Diggle to rely on one another, despite Diggle's anger from the previous episode. Through A.R.G.U.S.' support, Lyla was able to give Team Arrow everything they needed to dig into the Arrow cave, including an upgraded version of Curtis' T-spheres. Lyla admitted to stealing his design, but in this case, it was a good thing that she did.

Diggle made the most daring rescue attempt of the night, which put him directly in harm's way. Diggle was the hero this week. He also realized that he needed to forgive and trust Lyla for working in the morally gray areas because Team Arrow works in those same morally questionable areas all the time. He and Lyla stitched up their relationship by the end of the episode, which was a comfort to anyone who's been rooting for Mr. and Mrs. Diggle over the course of the series.

Learning to Trust Again

Arrow Felicity

While Tem Arrow was working above ground, Oliver and Felicity were trapped beneath it. Prometheus had rigged the Arrow Cave with an EMP device, which knocked out anything with power, including computers, elevators, doors, and escape routes. While neither Oliver nor Felicity were injured in the first blast, the EMP did knock out Felicity's back implant, which meant her legs were completely immobilized.

Oliver's first plan was to climb up the elevator shaft. Felicity warned him that it could be rigged, but he didn't listen. He was caught in a blast and was severely injured during his fall. As Oliver and Felicity continued to find a way out, the episode cut to a series of flashbacks from a few months prior. Oliver and Felicity were wrapping up a day of work in the Arrow Cave and Curtis set them up with some dinner and wine. After food, drinks, and turn on the always sexy salmon ladder, Oliver and Felicity started kissing and then made love. This took place somewhere between Oliver and Felicity's breakup and the beginning of the season when she was dating Billy Malone. When they were finished, Felicity confessed that while she still loved Oliver that she still didn't trust him.

This conversation was circled back to a few times while Oliver and Felicity were in the bunker. First, while Oliver was on the brink of passing out from loss of blood, he confessed to her what Prometheus revealed to him, that he was a killer. Later, just when they thought they were going to die, Oliver also confessed that he always trusted Felicity, he just didn't want her to become like him. These truths were long overdue, considering Oliver and Felicity almost got married but never revisited the breakup afterward.

Diggle's daring rescue came just as Oliver and Felicity were running out of oxygen. With Felicity strapped to Oliver's back like Yoda in "Empire Strikes Back," Oliver had to jump to find Diggle's hand and pull Felicity up with him. At one point he almost lost her and she was willing to let go, but he pulled her up and Diggle and Rene saved them both. It was an incredible sequence of events where the stakes were palpably and powerfully felt. If Oliver had dropped her or Diggle had dropped him, it would have been game over. Thankfully Oliver and Diggle both have arms of steel, so everyone made it out safely.

The episode concluded with Oliver making it through surgery and Felicity reminding him that he was a good man and not a monster. She also told Oliver that she finally understood why he didn't tell her about his son William. That lie led to their breakup because Felicity wanted Oliver to be 100% transparent with her. When he couldn't be, she let him go. Now she knows what that feeling is like, what a small piece of Oliver's struggle was about. While it didn't look like Oliver and Felicity will be getting back together right away, at least they got to clear the air, which counts for something. Speaking of William, despite being in witness protection, Prometheus found him, which means William's life will be in grave danger in the next few episodes.

The Sins of the Father

Next week Prometheus continues to play games with Oliver, first by delivering a corpse to his office. The episode is called "Honor Thy Fathers," which was an episode back in Season 1 where Oliver went after Martin Somers, a man on his father's list. Perhaps that name will come up in the episode or have a connection to the dead body. With only three episodes left in Season 5, Oliver only has a short ammount of time to beat Prometheus once and for all.

CHASE CONTINUES TO TORMENT OLIVER – Oliver (Stephen Amell) returns to the mayor’s office and faces one of his most pressing issues yet – the forced release of dozens of violent criminals prosecuted by Adrian Chase (Josh Segarra). Meanwhile, a crate is delivered to Oliver’s office containing a mysterious corpse encased in concrete. Laura Belsey directed the episode written by Marc Guggenheim & Sarah Tarkoff. Original airdate 5/10/2017.

Starring Stephen Amell as the Emerald Archer, “Arrow” airs Wednesdays at 8 pm ET/PT on The CW. The series also stars Emily Bett Rickards, David Ramsey, John Barrowman, Willa Holland and more.