In the year 18 BBY, Echo and fellow members of the Clone Underground spearheaded an assault on a prisoner transport vessel. The operation aimed to free Howzer along with the two remaining members of Howzer's squad, all within the Balmorra system.
More than a year before this rescue, specifically in 19 BBY, Clone Captain Howzer, then stationed on Ryloth as a leader within a squad belonging to a larger battalion, openly defied the authority of the Galactic Empire. He urged his troopers to join him in resistance. While some of his squad did support him, Howzer and his rebellious comrades were immediately apprehended and placed in Imperial custody. Over the subsequent year, six of the eight squad members who initially sided with Howzer perished while imprisoned by the Empire. Ultimately, Howzer and the remaining survivors were selected for transfer to an Imperial facility located on the planet Wayland. They were escorted onto a Gozanti-class cruiser by TK stormtroopers and a clone commando, and the ship set course for Wayland.
Not long after its departure towards Wayland, the Imperial vessel was caught in an ambush orchestrated by a ship commanded by the renegade Clone Captain Rex's resistance network. This network had received intelligence about the transport from a source embedded within the Empire. Unable to engage hyperspace travel due to the damage sustained in the initial attack, Captain Pearce instructed the ship's pilots to return fire and request reinforcements from Imperial command. Recognizing the urgency of the situation, the rogue clones Echo, Fireball, and Nemec swiftly boarded the Imperial shuttle using a leech vessel. Meanwhile, Pearce ordered his TK stormtroopers to brace for boarding, leading to an intense firefight between the Imperial forces and the rogue clones. As the ship's stormtroopers were rapidly overwhelmed, Pearce commanded an Imperial clone commando to wipe the ship's databank to prevent its data from falling into the hands of the rogue clones. Echo and Nemec quickly reached the bridge, neutralized the commando before the data wipe could be completed, and held Pearce at gunpoint. While Echo worked to recover the remaining data, Nemec demanded Pearce reveal the destination of the ship's prisoners. Instead of complying, Pearce activated a suicide shocker, resulting in his immediate death.
Soon after, an Imperial Venator-class Star Destroyer arrived from hyperspace in response to the Gozanti's distress call, deploying a squadron of Alpha-3 Nimbus-class V-wing starfighters. As Echo, Nemec, Fireball, and the freed prisoners escaped the ship, the Imperial starfighters bombarded and destroyed the Gozanti-class cruiser. To avoid becoming targets themselves, the rogue clones jumped to hyperspace and successfully escaped.