Many leave or get fired by the minute. guess what - performance is never the issue - those workers wanted to prove themselves, wanted to do something meaningful, but somehow failed in "playing the game" and they couldn't stay anymore. Ppl leave because they had enough, and realise how so little they developed their skills for the time that they spent in the company. The HR never care - they will find a replacement, yes, some like to come for a 2 years shift to see this un-real place.