Heh, I was actually playing with the comment, status, and some other commands to see if they would flush the buffer automagically, but they didn't work. However, I didn't go so far as to try to overflow the buffer, but now that you mention it that might be an easy trick to pull off.

Comes back 30 seconds later...

The buffer is 4KB. Problem solved!

Interesingly, only works if I unbuffer the output using fctrl.