My reading is:
The RRG states that activation occurs and that the first task in activation is to show the command dial. However, in the Flesh Ripper’s case, their activation is modified by the before clause with states in 83.7 that a before clause occurs immediately before the specified event. The event is not “activation”, that is a phase, the event is the first event of activation the display of the command dial per RRG 5, step 1 – Activation. So you could read the instruction as “Initiate a unit’s activation phase but, before performing step 1 of Activation - Revealing Command Tool, you must perform a speed-1 [march].