The only way to do this is to fool the control.
On the spindle contactors there are "piggy back" contacts. These tell the control that in theory the contactor is pulled in and thus the spindle is running.
Maybe if you jump this out (make a connection) the control will run through the program. check wiring diagram for wire numbers.
2nd alternative: pull it into neutral.
3rd option, in the RUN screen you can say no Z and max feed. May fault in a G2 or G3 as it whips the table.
Option 4: use preview.
George
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)