I do not understand why concerning heros there are two plots for explore actions and only one for move action. Due to the fact I must finish an action to begin another one, I see only on occasion to use to action explore twice : begin on an unexplored tile, doing an explore action, move on an unexplored tile and explore again.
Do you see others cases ?
I will just say that the safest way to explore is to start your turn on an unexplored tile. Especially if you know its a creature.
EXPLORE if possible (only if you know its safe.)