It's possible for him to loop.
Get a trigger_auto, set it to 0.1 on "Delay before trigger"
Put the name of the scripted_sequence in "target" (Example : EK)
And do the following in the scripted_sequence
Name : EK
Target : EK
Target_monster : Name of worker
Repeat rate ms : 400
Check repeatable (Not sure if it does anything.)
Of course, he looks like his humping the floor.
But it's the best way to do it if you don't know anything outside of Valve Hammer.
EDIT : Maybe there's a better way.