HR and Technical Team put lot of effort in Interviews. You have seen walkins are conducted on weekends, which is usually off for Tech team. In walkin if there are 100 candidates to be interviewed, than the best is selected. There are diffreent rounds of interviews, Hr screening, 1st technical, 2nd technical etc. If you clear the 1st round than you will be asked to sit for 2nd round and so on, but in walkins offers are not made. a pool of selected candidates is created. Say we short listed 10 people, so out of these 10 we will decide on the best candidate first, and than cosider others, depending on their experience, teachnical knowledge, education background etc.