More than a flesh wound
In the wash-up, Laura herself loses an arm. Until it is sewn back on, the character remains arm-less (well, Laura carries it around with her). But it did mean that Browning's real arm had to be digitally removed, and the actress also had to 'fake' not having the appendage.
"Emily was really great and she was very conscientious of her arm," says Ball. "She had a thing where she liked to tie it behind her back in a way, to sort of ball it up in a fist and fold it behind her back, because for her that just helped her feel a little bit different and feel a little bit crippled."
Browning wore a blue screen sleeve, with the idea being that visual effects artists (from Base FX in China) could then isolate her arm and remove it. They also re-built parts of the frame that the bluescreen sleeve was covering, and added a stump to Laura's shoulder.