Torres for Barca is because it's 90th of the minute of the game and Barca are about to be knocked out of CL. At that point, everyone goes up. If the ball went for a corner, the goalie would come up as well. I'm assuming it's something similar for that Salah goal as well. Context matters as well.
I still don't understand the reasoning by Chelsea there - any Liverpool fan watching the previous year knew he wasn't the same after that injury. Carragher says basically exactly that here (though the Andy Carroll buy was interesting as well): https://youtu.be/58hK8XnwJVQ?t=1050
Salah vs Manchester United: https://www.youtube.com/watch?v=STjxoGgFIzk
Torres vs Barcelona: https://www.youtube.com/watch?v=lKOXBLTsu3s