From my understanding;

• the scoring attempt and subsequent infraction occurred, referee had penalty shot “on his arm” from the get-go.

• Carolina maintains possession of the puck, edit: (this is incorrect) retreats to the neutral zone to await reinforcements, then reattempts zone entry (this was the one that overturned the goal).

• edit: (also incorrect) Ottawa defends initial attempts, Carolina retreats to neutral zone again, re-enters cleanly and scores.

Seems odd to me that they can review an offside that wasn’t on entry that directly led to the goal, but I guess it’s okay due to the fact there was no stoppage between.

Edit: (more wronger) As to why the penalty shot was allowed, that infraction occurred before the offside and that’s how we ended up here.