My understanding is that after several incidents of pilots shutting off the wrong engine, the training was overhauled so that from day one they treat fuel switches as sacred. I heard that it’s required to ask for confirmation before toggling the switch, just to be absolutely certain. It’s not really something that can be done by muscle memory during flight, and especially not during takeoff.
If he was trying to do something else, he would have called it out. E.g. an audible “gear up.”