without breaking (one's) stride
Without stopping or slowing down while walking or running. The forward made a masterful and elegant pass back to the striker without breaking her stride. Police say the man was walking down the street and then, without breaking stride, snatched the woman's purse from her table.
without breaking ˈstride
(especially American English) without stopping what you are doing: The police officers looked at him as they passed, but walked on without breaking stride.