diff --git a/src/npc.cpp b/src/npc.cpp
index 3d2900994c..0479821f93 100644
--- a/src/npc.cpp
+++ b/src/npc.cpp
@@ -479,8 +479,9 @@ bool Npc::canWalkTo(const Position& fromPos, Direction dir) const
 bool Npc::getRandomStep(Direction& dir) const
 {
 	std::vector<Direction> dirList;
-	const Position& creaturePos = getPosition();
+	dirList.reserve(4);
 
+	const Position& creaturePos = getPosition();
 	if (canWalkTo(creaturePos, DIRECTION_NORTH)) {
 		dirList.push_back(DIRECTION_NORTH);
 	}