Refusing orders

[Tarbicus]

What do we mean by "disobediance"?

Here's a variant on an example:

A particularly cruel tribune orders a legionary to cut the throats of a group of villagers in Germany for no reason. The legionary refuses because they have done nothing wrong and feels compelled to disobey

Or:
A particularly cruel tribune orders a legionary to cut the throats of a group of villagers in Germany for no reason. The legionary refuses because they have done nothing wrong AND the legate has ordered that there will be no uneccesary killings in order to keep the peace.

Or:
His comrades start to do it, but a legionary tries to intervene for the above reasons.

Feel free to swap the legionary for a centurion or optio.

I know attitudes were different in those days, but refer to Hugh Thompson's actions at the My Lai massacre I posted at the start of the thread. This is pure conjecture, and I was only really asking if anyone knows of any literary evidence for such a thing, which I highly doubt somehow.