User blog comment:Morganaforever/Series 4 Cliffhanger/@comment-141.0.8.200-20120223135649

I have two theories to the mistake merlin did or commited in the series that the merlin producers were talking about in the interview and will become a greater plot in series 5. the first theory or mistake merlin did is helping morgana and arthur to send modred back to the druids and not allowing him to be killed in series 1. the great dragon told merlin to do nothing as the boy will in future kill arthur. but he instead ignored the dragons advice and let modred escape. 2. the second mistake is merlin still seeing the good in morgana or still remembering the friendship they once shared and not being able to kill her, even to the extent of teleporting her out of camelot and using his dragonlord powers to send aithusa to heal morgana and saving her. these two theories are very likely the mistake merlin did that the producers were talking about in that interview. this two mistakes that merlin has commited will come back to haunt him or even prevent him from fulfilling his destiny in series 5 as modred and morgana will be united in evil as the great dragon has prophesy earlier in the series. aithusa also cannot be evil as he was just following the orders of his dragonlord merlin. these are my own reasons or theories anyway. do not get me wrong, but i am very sure the mistake the merlin producers were saying could be one of them or even both.