On LU, reversible standard width gates have the following settings:
Open - Paddles opened, with Oyster readers active on the side they were last serving
Closed - Paddles closed, with Oyster readers at red on both sides.
Entry - Paddles closed, with Oyster readers active on the entry side.
Exit - Paddles closed, with Oyster readers active on the exit side.
EMO (Emergency Open) - paddles open, with oyster readers active on the exit side.
On WAG (wide isle gates), there is an additional setting-
FCFS (First Come First Served) - Paddles closed, with oyster reader activity switching from one side to another, to serve both sides but without letting two people through at once in different directions.
There is also the ability to switch the gate off, (often described as a 'hard reset'), but that would usually be done to only 1 gate at a time and that gate would be blocked by a member of staff serving it. There would be no light on the oyster reader or the gate display with the gate 'hard off'.
Usually, when gates are opened for crowd control purposes, (to avoid delay when exiting), when not in an emergency situation, (like a station evacuation, where EMO would be used), the gate array would be on 'Open', (having been in 'Exit' prior), with paddles opened and oyster readers active on the exit side.
As others have suggested, it would have been likely that you could have touched out - that said, mistakes do happen. I am unsure about the automatic measures now implemented as I am not working on station side anymore; however I am sure a call to the OCC or a visit to a ticket office would be able to get this rectified.