I think Weir thinks that if she shows doubts, her entire team will collapse. The only thing keeping them going is hope, and the more desperate the circumstances get, the more she tries to project confidence. The Genii occupation had to have shaken her deeply, but she still had to be calm and in charge in the aftermath. And once I started thinking about it, there were a lot of details to take care of after the storm - the dead, the injured, securing Sora (who I regret not mentioning), the Athosians, repairing Sheppard's sabotage. There's a lot we didn't get a chance to see on screen.