LYNN – A judge ordered $500 cash bail for a city man who allegedly showed up at a neighbor’s door brandishing a chef’s knife, but also expressed concern that a combination of the man’s mental-health history and a volatile living situation could be “critically explosive.””I’m concerned about what I’ve heard about as far the other matters, where he is in a situation that seems to be critically explosive,” Lynn District Court Judge James Wexler said in Lynn District Court Wednesday. “I’m not sure what causes it, but it sounds to me like something is going to be bad here, sooner rather than later.”Richard S. Cushman, 33, of 38 Hanover St. #6, was arrested and charged with assault with a dangerous weapon at 5:49 a.m. Wednesday. He was arraigned on the charge later that morning in Lynn District Court where a plea of not guilty was entered on his behalf.Officers responded to the Hanover Street apartment complex early Wednesday and met a woman who said she was awoken by loud banging on her door, Lynn Police Officer Michael McHale wrote in a report.The alleged victim told officers she opened her door and found Cushman, her neighbor, holding a “chef’s knife” and moving toward her threateningly but not saying anything, according to police.The woman allegedly was able to close the door, although Cushman was pushing against it, and she subsequently called police.Police said that after interviewing Cushman, it was “obvious (the defendant) has some form of mental disorder,” but the defendant could answer officers’ questions and follow commands. (A court clinician testified Cushman appeared competent and able to understand and explain the court process.)Essex Assistant District Attorney Jacquelyn Kaplan said Cushman had a record of previous violent incidents and the record showed he had “benefitted from the leniency of this court and Salem court as well.” Kaplan requested $1,000 cash bail.Probation Officer William Norcross raised concerns about Cushman’s mental health and “volatile” living situation, where he was the target of harassment.”There are a lot of racial slurs directed at him, feces thrown at his door, urination on his door, it’s hard to explain,” Norcross told the court. “There is open drug use in the hallways and cellar? we’re trying to get him out of this location.”Norcross cited an Item article that day in which a district fire chief said the Hanover Street address and its neighbor generate many “malicious” false fire alarms, prompting fire officials to request police accompaniment when they respond to the buildings.Norcross said he had to visit Cushman in his apartment because the defendant was too afraid to leave. (In the story that appeared that day about the false alarms, the building’s landlord said he has been trying to evict problematic tenants.)Norcross requested Cushman continue working with probation to find a new apartment.Court-appointed defense attorney Sam Gates echoed this suggestion and requested his client be released. But he said it was “a difficult situation.””In asking for personal recognizance it’s returning to a place that’s been described as having some of the worst conditions,” Gates said. “He’s someone who is constantly harassed where he lives.”Gates requested the alleged victim’s board of probation record also be admitted into evidence.Wexler allowed the request and set $500 cash bail for the charge.He scheduled Cushman to return to court June 6.