> [Gjarna is about equal to the German gern - and in
> Bjarni's remarks I see criticism - is he implying the lad is a coward
> for his fear]

Yes, ON 'gjarna' is cognate with German 'gern(e)'. Nicely human touch
to the heroics here: he's brave enough to lay down his life for his
comrade, but not above making some pointed remarks about him in the
process.

> fóru leiðar sinnar
> went away

"went on their way"