['alien', 'flee', 'EmptyParameter', 'impulse', 'at']
["Synset('imaginary_being.n.01')", 'escape-51.1', 'EmptyParameter', "Synset('movement.n.03')", 'at']
The aliens flee at impulse, one of their engines leaking plasma.
the Synset('imaginary_being.n.01') flee at impulse, one of <PRP> Synset('wheeled_vehicle.n.01') leaking Synset('chemical_phenomenon.n.01').