You are running in synchronous mode, so "process continue" won't return till the process stops for some reason. You didn't set any breakpoints, so short of crashing, there's nothing to make it stop.
If you want to have more control over handling the process as it runs, you might want to try modifying the event-handling example at:
http://llvm.org/svn/llvm-project/lldb/trunk/examples/python/process_events.py
to your purposes.