The latest episode of The Flash season 6 borrowed Batman's method for defeating the Justice League in order to save Barry and halt the machinations of Bloodwork. After what many considered to be one of The Flash's best-ever episodes, "The Last Temptation of Barry Allen, Part 2" picked up the action almost immediately after last week's monumental cliffhanger. All but entirely consumed by Ramsey Rosso's sentient infection and now dubbed "Dark Flash" by Cisco, Barry helped to expand Bloodwork's reach. With The Flash forcefully bringing in new and unwitting hosts for him to infect, Bloodwork soon had control over a large population of what he called "Blood Brothers". Seeking to expedite his plan for citywide control, however, Bloodwork soon turned his attention to Star Labs and its infamous particle accelerator.
Having been previously knocked unconscious by Dark Flash, Frost, Iris, and Cisco all awake to the chaos raging through Central City. Fortunately, Cisco is more than prepared - springing into action and activating security measures that include a forcefield around Star Labs. As he does so, an announcement blasted over the facility and revealed that "Babel Protocols had been initiated". The Babel Protocol was first teased in The Flash season 4 as part of Barry Allen's new suit at the time. As Frost pointed this out, Cisco revealed that that had been version 1. Version 2.0, however, is designed to ensure that nothing can get in or out. Cisco went on to reveal that he built such measures for if The Flash ever switched to the dark side.
What some fans will recognize and what some others may not know, however, is that the Babel Protocol is a term originally coined by Batman. Written by Mark Waid and published in 2000, JLA: The Tower of Babel dealt with the revelation that Batman had secretly amassed records on each member of the Justice League - most especially their strengths and weaknesses. Ever the pragmatist, Batman had used the gathered intel in order to perfect techniques for neutralizing the Justice League members should they ever veer from the path of light. They included trapping Wonder Woman in a virtual reality battle that she couldn't win but from which she would never surrender, blinding Green Lantern, and rendering Aquaman afraid of water and thus sentenced to death within a matter of hours. As a result, the Justice League was subsequently divided on whether or not to allow Batman to remain a member.
Fortunately, Cisco wouldn't have to face such repercussions. As he and Iris learned that Barry was still somewhat conscious beneath Bloodwork's control, they ultimately lowered the forcefield and allowed Bloodwork and Dark Flash to enter. Once inside, Barry is able to resist long enough to keep from killing Iris and Iris herself is briefly able to incapacitate Bloodwork. All of which gave Allegra time to finally embrace her powers and send a wave of UV rays across the city, thus eliminating Bloodwork's cells from each of the infected host bodies. With The Flash ultimately returned to normal, he was able to defeat Bloodwork and once again be the hero the world will need for the long-teased Crisis on Infinite Earths crossover.
Equally, it's unclear what other elements were into Cisco's version of the Babel Protocol - if any. After all, while a forcefield proved useful in initially keeping Bloodwork and Dark Flash out of Star Labs, it did very little to actually incapacitate the threat of an evil Barry Allen. Even gaining entry wouldn't have been too difficult overall, given that numerous Team Flash members bypassed the forcefield using of breach devices - of which Barry could have forcefully acquired from them at any time. All in all, it seemed merely like a way to protect themselves and the lab at the expense of the city, doing little more than buying themselves time to formulate an offensive strategy. As such, while Cisco is all set to become the new team leader on The Flash, he's still a world away from Batman's level of paranoia and planning.