Deliverance by What Power

Mat 10:1 And when he had called unto him his twelve disciples, he gave them power against unclean spirits, to cast them out, and to heal all manner of sickness and all manner of disease. Jesus gave His followers power

Mar 1:27 And they were all amazed, insomuch that they questioned among themselves saying, What thing is this? what new doctrine is this? for with authority commandeth he even the unclean spirits, and they do obey him. Because Jesus had the authority

Mar 3:11 And unclean spirits, when they saw him, fell down before him, and cried, saying, Thou art the Son of God. the spirits were subject to Him and recognized His authority

Mar 5:13 And forthwith Jesus gave them leave. And the unclean spirits went out, and entered into the swine: and the herd ran violently down a steep place into the sea, (they were about two thousand;) and were choked in the sea. Again, Jesus had the authority to permit the spirits to go into the pigs

Mar 6:7 And he called unto him the twelve, and began to send them forth by two and two; and gave them power over unclean spirits;

The "power" Jesus gave to his disciples is similar to "power of attorney". With someone's "power of attorney" you can conduct business in their name and on their behalf just as tho they were the one conducting the business. Therefore when confronting demons you must do it based on the "authority" of Jesus. That's why it is common for demons to protest before they are commanded to leave "don't say that name!" Then when you say "Jesus" they immediately protest, "I told you not to say that name", one even said in a whiney voice "oh, you said it".

Act 8:7 For unclean spirits, crying with loud voice, came out of many that were possessed with them: and many taken with palsies, and that were lame, were healed. It is quite common for unclean spirits/demons to "cry with a loud voice", scream, screech, yell, cry tears, rant, rave, throw the body around and just generally cause a ruckus when they are leaving the body where they've been residing. Afterall they are being kicked out of their house, and they are extremely unhappy about it.

Also, the hope is that the more obnoxious they are and the more of a scene they make that the person conducting the deliverance will get scared off and stop. I've noticed that the manifestations are much quieter when I simply take authority "in Jesus Name" and command the spirits to be quiet, forbid them to speak or make any violent gestures before the deliverance even starts.