A scan coordinate is missing from the Chaos Tunnels list. It is in the Ice Troll room in the south-west of the Chaos Tunnels, room 48 on this map. A picture of the location may be found here. The coordinate is one square south and three squares east of the blue burner/scrying pool.

And another one in the Chaos Tunnels:

 

It's in the small Fire Giant room(number 11 on the map I linked to in the previous post), 7 steps east of the western portal in that room; a picture can be found here.