<sod >He said: "She finished her last song .. and we heard like a really basey bang, and all I can remember is just everyone ... was just running out... people were covered in blood, some people were having a fight, it was quite scary." One tweet from a writer said: "A friend works in A&amp;< eod>< sod > He said: "She finished her last song .. and we heard like a really basey bang, and all I can remember is just everyone ... was just running out... people were covered in blood, some people were having a fight, it was quite scary." One fan leaving the concert described how the loud bangs resonated as fans were leaving the venue, which has a capacity of 21,000.< eod>