Perhaps. Perhaps her scream is not audible; I dont know how far the cave is and how noisy the party is.
But,
I'm not really sure of how much did your character drink at that party, but if I was a future guy in a crowd of primitive people, and all of a sudden saw how six of these almost ape guys take three of those that were on your team- and you see them go away- perhaps that would draw my attention.
Follow from a distance.
Or alert the others.
You can still mingle, also. You guys could be casually standing together when the cavepeople take their victims away, and start sensing something is just not right.
Or get creative in other ways; perhaps you find something useful among the cavepeople after all? Some drunk guy that left his weapon unattended?
Or get plotsy, and brainstorm with Zen to see how would ideas fit in.
If my character was not in the victims group, I'd be doing that one probably.
Simply suggestions.