> Kolskeggur vó þá mann og átti sem mest að vinna og kom hann eigi

fyrir sig skildinum

It confused me too, but MM & HP's translation says: "K. had just
killed someone and had no time to raise his shield", so presumably the
sense is that he had too much to do all at once.

> Þá mælti Starkaður: "Flýjum nú, ekki er við menn um að eiga."

Then Starkað spoke: `(Let us) now flee, (it) is not against men to fight.'

MM & HP "these are not men we are fighting", i.e. we're not dealing
with humans: they're trolls, monsters, so it's not our fault we're
getting thrashed!

LN