言われても / 覚えてろ

Hi,

1.
「どうしていまごろそれがショックなの？」
「どうしてって言われても」

The second sentence is translated from the English "I dunno". How is that meaning obtained from どうしてって言われても?

2. 「いまに—見てろ！覚えてろ！」

This is translated from English "You wait! You wait!", i.e. the speaker is promising revenge.

a) Is 見てろ an imperative form of 見てる?

b) Assuming, likewise, that 覚えてろ is an imperative form of 覚えている, I don't really understand the meaning in the context. Could it mean something like "You'll learn your lesson (when I get my revenge)!"?

Change どうしてって言われても to 「どうして」って聞かれても and it should be easier to understand. Imagine an unspoken (答えるのに困る) on the end.

1a. Yes.
2b. "You remember this!"....(because I'm certainly going to remember it, and you should have no reason to wonder why when I start stomping the dog snot out of you at some future date more to my convenience).

I just noticed I numbered my answers incorrectly. Oops.