In the behavior section of the monster data set you can find “Speed Variables”:
Here where you can set the movement speed of each state:
PlayerFoundReaction: The movement speed while playing reaction animation and start chasing.
Chase: Chase Speed after preceiving target and finished the reaction.
Searching: The speed of investigation or search after losing sight on target.
InitialState: The speed before precieving a target while patroling or wandering.
Hit: The movement speed while the monster getting damage.
Flee: The speed when the monster running away from the player.