[brief] Here, Petitioner was performing an activity which he had previously performed and for which he was hired and trained to do, i.e., carrying a hose from the fire truck to the fire scene.  Unlike the custodian in Brooks, Petitioner has admitted that he does not know why he fell.  Nor does Caminiti v. Board of Trustees, Police and Firemen’s Retirement System, 431 N.J. Super. 1 (App. Div. 2013), cited by Petitioner, bear any resemblance to the instant case.  In that case, a police officer who was struggling to frisk a raging and violent drug addict for weapons was pierced by a needle in the addict’s pocket.  This caused the officer to fear that he would acquire AIDS and necessitated a prolonged period of painful treatment with medications to prevent transmission of the disease.  Id., at 7-9.  The Appellate Division held that the incident involving the “potentially lethal needle prick” satisfied the Richardson factors, as it was a “singular event that occurred at a specific time and place by an external force....”  Id., at 21.  Here, Petitioner’s assertion that while performing his usual duty in the usual way of carrying a fire hose to a fire scene, he twisted his ankle but does not know the reason why, bears no likeness whatsoever to the “singular” and violent external force which led to [...]’s injuries.  Much more comparable to the instant case is [...] v. Board of Trustees, Police & Firemen’s Retirement System, 2024 N.J. Super. Unpub. LEXIS 164 (App. Div., February 2, 2024).  [RA - Exhibit “D”]  [...] was a firefighter who claimed that his left shoulder was injured while he was responding to a fire.  As he was unloading or “stretching” a supply line from the fire truck to connect it to a hydrant, he got jerked back and felt pain in his arm (Id., at 1-2).  When asked what caused him to be jerked back, [...] responded that “apparently” the accident was caused by a lump sum of the supply line, “guess[ed]” that “one of the couplings got caught or something” and “believe[d]” that the supply line must have been stored incorrectly (Id., at 2).  [...] testified that he received much training on loading and unloading hose beds, hooking up hydrants and stretching hose lines, and that in his years as a firefighter he had responded to hundreds of fires (Id., at 2-3).  The Board denied [...]’s application for AD and after a hearing, the ALJ affirmed.  The ALJ noted that [...] could not articulate what occurred on the accident date as evidenced by his use of the terms “apparently,” “guess[ed]” and “believe[d]” (Id., p. 4).  The ALJ determined that there was no evidence of a traumatic event that was undesigned and unexpected, and the Board adopted the ALJ’s decision.  Ibid.  The Appellate Division affirmed, finding that the ALJ’s decision was based on ample findings supported by substantial credible evidence in the record and was not arbitrary, capricious or unreasonable.  Id., at 7.  So too should the ALJ’s and the Board’s decision to deny AD to Petitioner here be affirmed, as Petitioner admitted he does not know why he fell (Aa18), and his testimony further shows that at the time of the incident he was performing job duties for which he was trained and which had performed on previous occasions.  As the incident involving Petitioner was not undesigned and unexpected, as required by Richardson, the Board’s decision to deny AD should be affirmed.