There is almost too much to retrocon.
Zelda cast the spell on coin given to Ramad who is back away from the guard's room so they couldn't see it until he ran into battle presumably with a double-move action.
However, as Starhawk pointed out, perhaps another PC should have been chosen.
As Eborne said, perhaps that coin could be given to another however.
_________________________________________________________________________
Also, the DM placed the darkness spell in an area or presumed that Ramad moved up which spooked the guards into sounding an alert and moving back, even though the spell was cast and should have remained outside their point of view.
It kind of just got accidently messed up a little is all.
__________________________________________________________________________
I suggest we simply play through the matter and move forward. :)