I've seen the TSA direct those appearing to need extra time to unload on a separate belt.

I do like to keep things moving. If for some reason, I'm fumbling with something and holding up the line, I'll tell the person behind me to jump ahead.

I've also seen the TSA direct people to come forward of someone who is running slow.

I don't jump the queue, unless directed to do so.

If there is a line to the lav, does the OP queue-jump as well?