Airspeed and pattern type (DBF or Figure 8) are unrelated. One can do Figure 8’s while keeping good airspeed and also increase their sink rate compared to a gradual (low roll) DBF pattern. I have seen a few pilots inappropriately apply significant braking while on the downwind phase of their DBF (maybe spooked by the high ground speed). #AirspeedMatters.
As Jana mentioned, all areas in/around the LZ equally at risk of twisting air (visible dusty or invisible vortex). Lots of dust devils seen at the base of the HG training hill, after that area had recently been resurfaced and dust was available. Then back to more dangerously stealthy, waiting to snag the non-believers.