That person is taking orders from another person. But they are doing something dirty and trying to see 2 things.
1. How many more shares can we get before it go time.
2. Trying to steal shares from people that have entered stops in to try and protect profits. I know first hand that they will drop the pps just to get your stop to exercise and they will tick it down to ensure they are profitable.
People need to stop-setting-stop orders as the MMs and pros love to steal shares