The pain she felt when her brother died, she never wanted to feel that again but she did, her beloved was…well he was gone and now it was only her. She had stepped through that door years ago and was now an Avenger, she had to keep fighting to save the world or die trying. She screamed so loud when Vision got… She felt as her power went out of control. It was attacking all of the beasts Thanos sent at them.
Until she didn't feel like she was in control any more. The power surged through her veins causing her to burn. She looked down and her arms were on fire. Her magic was burning her from the inside out. Steve screamed at her and so did Nat but she couldn't do anything she was frozen there in shock. The pain didn't even register.
She watched as Steve ran up to Thanos with that smug smile as he had the Mind Stone, the source of her power. The gem glowed around him and then stopped as he plopped it in his glove. Steve put his hand around it fighting him. She saw no more