Hey! The math doesn't check out! More xenos than there could've been.
The thing with ropes that help them get down to the tunnel has six slots, so obviously they went in two turns to bring down a total of 12 people. In a couple of establishing shots you can only ever see 12 at a maximum. Later on in the sacrificial chamber, 5 people can be seen left behind to get facehugged, which is too many considering that in the other group:
2 get killed by Predators (one strangely choke, one throwy spear)
1 falls through the floor and is facehugged
2 more get facehugged (Van Halen and Jewy rat Scotsman doctor)
1 Sebastian gets facehugged
1 Bishop killed by Predatumz
1 The dindu main character survives
That brings the away team up to at least 13 people unless I missed someone. How the hell?! Rushed production??