To rush about on errands; to be kept busy or on the run while carrying out a task or mission. See 疲于奔命 pí​yú​bēn​mìng for the common phrase meaning 'exhausted by the rush'.

(Colloquial) To be in a desperate hurry; to dash or run at full speed; to work or travel with frantic effort.

(Literary) To convey urgent orders or relay emergency commands.