That’s why i love books.
Why does no one ever talk about Andromeda Tonks I mean she was a pure-blood Slytherin in the Black family and she still chose to marry a muggle born despite being disowned and then she raised one of the most badass witches in all of existence and joined the Order of the Pheonix and when her husband, daughter and son-in-law all died in the war, she stepped up and helped raise Teddy seriously that woman was a fucking hero.
They’re pouring latex on him to make a false chest. So that they can place the arc reactor prop in him and make it legitimately look like it’s embedded in is flesh and with tears and scar tissue. The latex is colored so they can see where they are applying and how thick the layers are. It will then be airbrushed to his skintone and details like nipples scar tissue discoloration will be added.
Here’s that picture
Then the reactor prop is added to the dimple. Basically the latex becomes fake skin and they tear part of the center open to embed it.
Now you can see how realistic it looks.