William was close to the bottom of what happened. The man didn't see them, only felt like someone was spying and watching. The thing is that this scene just happened at the same time as they were spying, and that allowed the man to take action.
Yet the man didn't do it, he borrowed the strength of the spirit backing him up and managed to sever such a connection between them and him.
"We learnt tons of things, but ended up with nothing…" Lara suddenly shouted in frustration, feeling rage like no one else was here. This was her home, her city, where her friends and family lived. She didn't like that someone was trying to damage it, didn't like that there was a great danger looming and coming towards her, and she did nothing in her power to stop it.