Seems like a lot of folk in that time volunteered for the quick trip to Valhala.....the seer never quantified "the god's smiling" on her - could be an ax whizzing through the air and her pretty head rolling off...
Not to pick, but Siggy would not go to Valhalla. Valhalla is Odin's hall for half of the men that died in battle and Valkyrie's only, the other half go to Freyja's field, Folkvangr .
Women would have possibly gone to Helgafjell or Hel.
The writers do a pretty good job of following the mythology properly.

