The action command most certainly does work, however there are some rules which need to be followed in order for the command to work.
The command cannot be taken verbatim from the unofficial comref (at least for me...). Using "STR_ACTION_EJECT" won't work, using "EJECT" will. Second, some actions have secondary requirements which have to be used with the action itself. For example, "soldierOne action ["Eject", SomeUnit] won't work because you haven't told the unit what you want him/her to eject from. This is why the official comref has the action command documented as "soldierOne action ["eject", vehicle soldierOne]". The first word in the command, "soldierOne" tells who the action is going to be acting upon; "vehicle soldierOne" gives more necessary info for the rest of the action to work (in this case, what to eject from).
While most of the secondary action requirements are undocumented (I think, someone plz prove me wrong) most are logical enough.