Southborough, MA- September 13, 2017: Connor Biscan, 13, swore at his teacher, Matt Souza, after a misunderstanding at the New England Center for Children in Southborough last September. Souza had erased the checkmarks on a chart that Connor had earned for good behavior the previous day. Connor was quiet for a moment then tried to punch Souza. Staff urgently pulled Connor back into his classroom and closed the door as Connor, upset about the blank chart, threw chairs. Connor then retreated under a desk. Souza was eventually able to calm Connor and they cleaned up the room. "You can't get flustered,'' Souza said later. "You never know when it's going to come. When it does you have to know how to react." (Craig F. Walker/Globe Staff) section: metro reporter: kowalczyk