When Shosanna (as Emmanuelle) shot Fredrick down, she takes a quick look at the screen where she can see a scene with Fredrick (the actor). When she looks back at Fredrick, she recognizes that he still seems to be alive.
She then approaches him, but without any caution. As if she is concerned for his health.
Why is that?
She could have easily shot him again. Or did she ran out of bullets? But even then she could have tried to smash his head with something lying around.