Dynamic Upload path error

trying to make a dynamic path when uploading af file with the following as path:

/users/{{$_GET.uid}}/company/logo

{{$_GET.uid}} is session id on the company, so the file gets uploaded in the right companys folder.

The path gets created and the file uploaded in: users/company/logo, so it ignores the {{$_GET.uid}}

What am I doing wrong ??