1- Asked updated docs before medicals for verification/updated record of documentary proof u have provided like JOB, Degrees, Transcripts etc etc
2- Asked for medicals when all above mentioned checks are over, Security checks are started after medicals or sometimes along with issuance of medicals from embassy
in simple words usually background checks are always replied by VO, according to Jimmy's wording " this background checks reply is all bakwas, its just a lollypop by Visa officer, bottom line is VO has to complete prescribed time for particular category in which that specific application falls, like for MI-1 applicant they have a time frame of average 3 years to grant visa, so they will always reply u that BG checks are going on but actually they are following there time frame, once u reach near time frame everything goes like rocket and u get Visa "
Hope u understand