Sometimes you can. In one story whenever the outline was stymied I set something else on fire, because there was a fire demon loose.
But sometimes, shocking though it is to know, the monsters can be the foe without their object being to oppose the hero. Or even to work random mischief, which works just as well -- or better, since then they would not need to know what the hero is up to.
Depends on the setting, too. In some worlds, monsters and marvels are so thick on the ground that the hero can count on stumbling on one whenever the outline drags.
But in a setting where the monsters are a part of politics, and the scheming may or may not admit of an attack --
Well, there just has to be some other way to send a man through the door with a gun in his hand. It's just that it takes rather more work.