Just do it with the modules turned off like Andrew suggests.

This would be very unsafe and could (if water or something else damaged the module) lead to something firing early even with the module in test.

I can see where this may be useful but I believe it would be hard for Cobra to implement, I am honestly trying to add some constructive thought to this topic. If the modules are set to "Test" you should be able to arm and run whatever script needed without anything firing. Once the Module is placed into "Arm", everything assumes it is go time. If you try to add a kind of middle ground state where everything is ready to arm but you don't want it to fully arm in order to dry-run a script. I feel like it would open up possibilities for things to go wrong.

I have had the need to modify a script the day of a shoot and that caused me to want to dry-run it prior to the display to ensure that I made the proper changes. In my case, I just done the dry-run before I turned on any of the modules. I do not leave them on during setup, I only turn them on to do continuity check during setup. I will then go turn them all to test once all the cues are placed to check signals. I will only arm my modules about 30min before start time. Maybe I don't do things in a conventional way. I just wanted to share my thoughts.