Hey, still on the Enclave side of the barrier, hands on weapons, surreptitiously. Not entirely stupid. 

The distance is too great for him to cover in a short enough span of time to give surprise. Messing with his head may buy time, or possibly make him more suggestible now that he's in a weakened state. Then again, Keystone's low CHA may be a hindrance in this endeavor. If the tactic fails, no harm done, Glith knows he's coming anyway. If it succeeds, he might be able to part him from his weapon without having to wrestle the undead bastich for it.

If Glith thinks he's a complete and utter moron, there's still no harm done. He already wants to do unwholesome things to Keystone, possibly involving his nethers and smithing tools. I'm mostly just buying time and moving closer.