Medan varken filmen eller manuset specifikt diskuterar vilka befogenheter amuletten äger eller beviljar, ger John det till Angela som en avdelning av sorter. Från manuset :
John turns to her -- locks on those eyes. He reaches into his coat pocket as he walks up to her. She shudders as his arms wrap around her face and for a beat they're cheek to cheek. When he pulls back she sees he has clipped Hennessey's AMULET around her neck. JOHN Think of it as a bulletproof vest.
Här är var skriptet och filmen avviker.
I filmen lämnar Angela olyckligtvis amuletten i bilen när hon tar av sig jackan och det är när John märker den saknade amuletten som Angela bortfördes.
Så, till Johns tidigare kommentar till Hennessey, är det rimligt att anta att det ger skydd mot attacker av demoner / halva raser.
När det gäller exakt varför han tog - eller, som i manuset, tog bort amuletten - låt oss se på manuset igen.
HENNESSEY Oh God, you want me to surf the ether. He instinctively touches an AMULET around his neck. Four intersecting crosses. JOHN Come on, you know that exorcism wasn't right. HENNESSEY I... I don't have the Sight anymore. JOHN Don't have it or don't want to use it? Hennessey vacillates. This is obviously tough for him. JOHN Just look around. A few days. You spot anything unusual, anything -- you let me know. Okay? John wraps an arm around his shoulder like a good buddy, then reaches behind his neck -- JOHN It'll be like old times. -- and unclips the amulet from Hennessey's neck. That unnerves the big guy. John drops it in Hennessey's pocket. JOHN Just for a few days.
Detta bakar upp tanken att amuletten är en avdelning. Genom att ta bort det hoppas John att demoner kan komma närmare Hennessey och han kan kanske lära sig något.
Slutligen har vi manusversionen av scenen där John och Angela hittar Hennessey i butiken.
John leans down to the remains of his friend. A cop starts to intervene but Angela blocks him. Let him be. John has trouble taking this in, reluctantly reaches into Hennessey's coat pocket -- finds the protective amulet he himself removed from his friend. That's even more crushing.
Den här sista biten bekräftar (IMO) åtminstone att amuletten var avsedd att skydda bäraren från demonattacker.