There is no command that allows an entity to teleport randomly. You could however create a "master" script attached to a trigger and allow the script to control entity(ies) by way of the command "random=x". For example...
1. Design your level. Let us pretend you place an entity on layer 5 dead center of the grid and called it "enemy1". A second enemy is placed on layer 8 top left corner and is called "enemy1l8t1". A third is placed on the 2nd layer bottom right corner and we call it "enemy1l2t2".
1. Master script uses "settargetname=enemy1",activatetarget=1" to focus on the entity on the map called "enemy1" and spawn it (providing you know how to set the entity to spawn when called).
2. Entity "enemy1" is spawned on the map where you placed it. The script for "enemy1" also needs to have a spot where it will check for a value passed to it, whether a variable or other method (such as "activated=1", "activated=2", etc.
3. Master script next will proceed with the "random=x" command. This command is as follows...
3.1.1.25 RANDOM=X
Description: Is true when a random number between 0 and X equals 0. I.e. random=1 gives a 50% chance of being true, whereas random=100 gives a 1% chance of being true.
Range: X = 1 to anything, although setting above 1,000 will make this conditions very unlikely to be true.
Example: :random=1:incstate
Along with this state you can script the random value then proceed to where you need to go. For example, "random=1" ensures a 50% chance you will go to the next spot you specify. The master script would then use the "settargetname=enemy1l#t#" according to what you point to.
The short of it is, with no direct command for random teleporting, you can achieve a work-around that "gives the illusion" using what is available providing you understand the script syntax.
There's no problem that can't be solved without applying a little scripting.