User blog comment:Toon Ganondorf/Read TG's raw live messages to Toast whist watching Series 9/@comment-2118191-20170322143658

Ground clearance wasn't the issue with robots getting stuck on the pit. The issue was in fact that the arena had been badly damaged, and whilst they fixed it up as best they could, they couldn't get all the kinks out right away due to timing...hence why the flipper was damaged in Episode 2 and hence why the pit gave way in Episode 3.