Truth be told, Angelina hadn't expected to be going after Oliver when she wrote her post. She hadn't exactly anyone to want to go after him. He was being foolish and selfish, but he'd never see that. Angie had just wanted Fred to follow him, to make sure Oliver was okay. And if he wasn't okay, Fred could get back to them. However, when Stanley suggested they go after Oliver, Angelina couldn't say on. Finally someone wasn't telling her to stay behind because she didn't have magic. Well muggles fought in wars, why couldn't she? It was rather foolish for Angelina to be going with Stan, since not only didn't she really know him, she barely recognized him. They'd been together only a few times, but Ang figured no one else would be coming to meet her.
Oliver wasn't the only person Angelina was angry at, she loathed Percy right now. It may have been Angelina's worry and anger deflecting onto someone else, but she had never really liked Percy. Ang gave Oliver unbiased advice on him, but otherwise Angelina couldn't care less about the redhead. Right now she hated him, and she was blaming this 100% on him.
Once Angelina reached the entrance, she waited. Going outside alone would be stupid, especially in her condition. Leaning against the wall, Angelina tried to breath. "Fred!" she called, hoping maybe he was in hearing distance. "I'm going after Oliver, tell Bill... and George." At the moment Angie was ticked at George, but she didn't need him to be uninformed, because that would just start a-whole-nother fight.