- "I just heard from my dad. He's been summoned to City Hall. Strange is requesting that Emergency Protocol 10 is activated."
"Does Gordon know what Protocol 10 is?"
"Just that it's the worst case security measure."
- ―Oracle and Batman[src]
Emergency Protocol 10, simply referred to as Protocol 10, was a contingency plan to exterminate Arkham City's criminal populace in the event of a potential mass breakout. It could only be authorized by the Gotham City municipal council and Arkham director Hugo Strange.
Protocol 10 was at the heart of the Arkham City concept as originally masterminded by Ra's al Ghul and Hugo Strange. Ra's and Strange planned to concentrate Gotham's entire criminal populace in a central location where it could be annihilated en masse, but needed a pretext for doing so. Through Mayor Quincy Sharp, they were able to successfully lobby for the mass relocation of all incarcerated felons and Arkham Asylum patients to the city's worst slums, which were then cordoned off as Arkham City.
During the new Arkham's construction, Strange first proposed Protocol 10 as a contingency designed to protect Gotham from the catastrophic crime wave which would inevitably follow any major breach in its heavily guarded perimeter. The contingency called for the immediate execution of as many inmates as necessary to preempt a mass breakout. Due to its controversial nature, Protocol 10 could only be authorized by unanimous consensus in the Gotham municipal council. Details were disclosed only to Strange, Mayor Sharp, and the city councilmen; even James Gordon and the Gotham City Police Department was just informed it was the "worst case security measure".
The task of carrying out Protocol 10 was entrusted to TYGER Security, a firm contracted to monitor Arkham's walled enclosure and keep the inmates under control. TYGER personnel were apparently briefed on Protocol 10 by Strange; it was understood that its successful implementation would conclude their contract with the city and set a precedent for similar programs in Keystone City and Metropolis.
To ensure Protocol 10's inevitability, Strange began smuggling weapons into the criminal populace from TYGER's arsenal. The proliferation of arms led to widespread gang violence and a bloody turf war between the Joker and the Penguin.
Batman: Arkham CityEdit
Batman did not learn of Protocol 10's existence until his own incarceration inside Arkham City, when Strange rather cryptically informed him that it would be implemented shortly afterwards. Strange then began an hourly countdown to its inception, which Batman monitored with increasing concern after hacking a TYGER communications network. He initially suspected Strange and the Joker were planning Protocol 10 in concert, since Strange had alluded to working with a partner. Unknown to Strange, the Joker, who was suffering from an incurable disease, was poisoning Gotham City's hospitals by smuggling his contaminated blood into the local blood banks. Batman reasoned this was Protocol 10, but when confronted the Joker claimed he'd never heard of it.
Strange called an emergency meeting of the Gotham City council and asked them to approve Protocol 10 by disclosing he'd failed to control the circulation of weapons inside Arkham. Under the circumstances, Strange insisted he was reasonably certain a breakout was about to occur. With the council's authorization TYGER was mobilized and commenced killing Arkham residents on sight.
Protocol 10 opened with a bombardment of Arkham City with unguided surface-to-surface missiles fired from Strange's headquarters at Wonder Tower. The missile strikes targeted three primary locations: the Solomon Wayne Courthouse, the Sionis Steel Mill, and the Cyrus Pickney Natural History Museum, and were intended to kill Two-Face, the Joker, and the Penguin, respectively. Meanwhile, detainees in TYGER custody - mostly new arrivals awaiting transfers - were taken to the basement of Wonder Tower and shot. TYGER helicopter crews patrolled the skies, utilizing thermal imagers to seek out and strafe individual inmates.
The missile strikes were largely unsuccessful; for instance, the museum survived with only superficial damage, and all three of the targeted supervillains escaped death. The heaviest casualties were inflicted on inmates caught out in the open, who were mowed down in the streets and on rooftops by the dozens. A number were also picked off by designated TYGER marksmen stationed on the perimeter walls.
After fighting his way through several TYGER platoons, Batman infiltrated Wonder Tower and gained access to Strange's personal computer systems, which Oracle was able to hack. The two of them were able to rescind TYGER's initial orders and cancel Protocol 10. Strange remained unrepentant over the destruction he had caused, calling it "glorious". Ra's al Ghul then revealed himself as Strange's accomplice before mortally wounding the latter for his failures. As he died, Strange activated Protocol 11: the destruction of Wonder Tower. Ra's and Batman were hurled from the structure in the ensuing explosion; although both survived, Ra's committed suicide to evade capture.
According to the Batman: Arkham Knight tie-in novelization The Riddler's Gambit, Protocol 10 resulted in hundreds of deaths, and damage on such a grand scale that it would be years before the affected districts could be reconstructed. The streets in particular were rendered unstable by the missile strikes. A few buildings which survived the actual bombardment, including the Solomon Wayne Courthouse and part of the old Gotham hospital, later deteriorated and collapsed anyway. The Riddler's Gambit also noted that several prominent inmates were able to take advantage of the chaos - and the subsequent withdrawal of TYGER following Protocol 11 - to make their escape.
Hugo Strange claimed to have eliminated 22% of Arkham City's population through Protocol 10. When Batman mentioned the casualties to Ra's al Ghul he received the dismissive response that the world would not miss them. Most of the subsequent political and media fallout from Protocol 10 focused on the circumstances resulting in its implementation (as well as the structural damage) rather than the death toll. Ironically, TYGER was scandalized for failing to control the inmates and keeping weapons out of their hands, rather than the extreme measures it took in killing them.
Surviving Arkham inmates such as the Riddler seized the opportunity to sue Gotham for huge sums of money and win their own freedom. Two-Face in particular made a fortune offering legal representation to former inmates taking legal action against the city for injuries sustained as a result of TYGER's actions.
- A number of dead prisoners in unique costumes similar to the Scarecrow appear on various rooftops during Protocol 10. They do not spawn at any point in the game and their presence has never been explained.
- Most of the Joker's gang survives Protocol 10 by barricading themselves underground in old sewers and the abandoned subway system. They openly taunt Batman and refuse to grant him refuge from the bombardment if the player attempts to interact with them.
- Two prisoners can be found hiding in a monorail car outside the Natural History Museum during Protocol 10. If confronted they will beg Batman to leave them alone.