Seems like a Loki flashback, if you put everything together. Harald died of an heart attack and Shanks helped the giants capturing Loki or some.
I don't know if I'd like a Shanks hype moment at the cost of Loki's hype hype.
I hope Loki is really excluded from the global power dynamic (Yonks/admirals/Pk contender) and thus is a big wildcard.
Involving Shanks might ruin that to a certain degree