The stalker has an limit on how much energy he can use with his abilities. Plus he has lost his previous memories so he is pretty much nerfed already in the start. Evem if he has the tenno armor with a shield to protect him from, its still limited to his energy stored within his suit that not only regenarate slowly through fift-teen posts if he has depleted all his energy that also takes out his shields. Forgot to add that to the cs hehe. . .