If the character is impatient and you-as-player want to play it as impatient, don't tell me up-front you're waiting for an hour. Tell me up-front you're waiting for 15 minutes, or however long you think your character can last without doing something rash.
Because yes, once you declare your action you're committed to seeing it through barring external interruption. For example, in the scout situation I might get the party to tell me how long they're waiting (let's say an hour) then go and play out the scouting. Let's say the scouting goes well and the scout would return in 45 minutes. Before the scout's player comes back, I return to the main group and see if anything has interrupted their waiting. Look, a wandering monster or patrol came by at the half-hour point, what would you do? And I play that out. Now that I know what happened there, I can go back to the scout player and tell her what she sees on returning to the party.