Anpu & Anput

When on an excavation site in Egypt, digging for the lost temple of Anpu and Anput, you stray away from your crew to get a drink of water. On your way to the well, you see two giant black dogs. One notices you and cocks its head as if willing you to follow it. It walks a few yards before nuzzling a button which opens up a cavern beneath your feet. You fall in and the dogs follow you.