I saw some continuity errors in the show. Particularly with the "death" of Arthur. Weren't Nathan and Peter informed about it BEFORE Peter took that cab ride?

I think Nathan told him before the court hearing, from what I recall.

Peter did already know about Arthur's "death" before going into the cab. What makes you say otherwise? Six Months Ago already showed us the scene where Nathan tells Peter. Just because they didn't repeat that scene, doesn't mean that it was implying that Peter didn't know it before going to the cab. They showed him going into the cab to make the little HRG/Mohinder connection and show that HRG was with Elle before going into the cab.

I've thought about that, too...

But it is a spirit walk, not a linear timeline. So we can say the scenes with Elle and Noah do not happen exactly at the same time with the ones with Nathan, Arthur, Angela, Peter and Linderman.

In the same set of idea, the wrecked train in which Claire save a man, it did happened during the season 1, aka before Arthur's ''death''.

I'd say that the Arthur timeline is the first, in a linear idea, followed by the Meredith timeline, then closely by the Elle/Gabriel/Noah timeline...

also when the epi began they said "18 months ago" and "one year ago" so there were differnt timelines going on.

Actually, the wrecked train was after Arthur's death, wasn't it? Arthur "died" in the events of "Six Months Ago" and the train thing was earlier in the season, ie, afterwards.

Well, exactly what I said!

The Arthur Timeline first
The Flint Timeline second
The Gabriel Timeline third

Which means the Arthur Timeline, aka, Arthur's ''death'', happened before the train wreckage. Well, my theory at least! They just showed it all in the same episode!

EDIT: I've just noticed that I said ''before'' when I meant ''after''! My mistake! lol