A crash in release mode usually means you are accessing a NULL or uninitialized pointer, that you haven't properly initialized a variable and use it before it is initialized, that you are trying to load a resource or something and then try to use it before checking if loading was successful, or any number of other programming errors. A crash is almost always your problem.

Running in a debugger under any IDE is different from running on the command line. The debugger generally initializes variables to known values so you can recognize them as such when debugging. Qt Creator also sets up an environment where resources and other things can be found when needed. Neither of these is true of the command line.