A fuel nozzle assembly for a combustor of a gas turbine including: a nozzle body having a front and an inner tube defining a fuel passage extending through the nozzle body, wherein the front proximate to a combustion section of the combustor; an outer casing around the inner tube, wherein an air passage is defined between the outer casing and the inner tube; a gas conduit arranged in the air passage and having an outlet proximate to the front of the nozzle body, wherein fuel starts flowing through the expandable conduit only after a flashback condition occurs in the combustor, and a premix fuel passage and port discharging fuel to a premix section of the combustor, wherein the gas conduit has an inlet open to the premix fuel passage.