The DEL to BOM flight takes off at terminal 3 lands at terminal 2. I've flow then domestic leg of these international flights before - you fly through the international terminals/gates but you get a ticket with a big D on it, and that lets you skip the regular counters at immigration (and prevents you from buying stuff at duty free or getting liquor at the AI departures lounge). So I thought that, if he was going all the way, he'd just get a ticket without the D, and go through immigration in Delhi and so wouldn't need to in BOM. Is that not how AI 191 works?