The disc is trapped on the sideline
The dump goes upline and doesn't get it
The dump cuts back and gets the disc...
... as his defender (1) swoops around to stop the swing
The dump give the disc back to the first thrower and cuts upline...
...for the easy score because his defender (1) was out of position
To stop this...
...when the dump cuts upline...
...and then cuts back to receive the break...
The dump's defender (1) will swing around as usual AND the new dump defender (2) must stop his man from getting the disc back until (1) can recover into a full mark...
...and the defense resets