I think it's one of those things where Loki's natural proclivity to want to manipulate events to his benefit came into play, and did create a dangerous scenario. But i think that act in Thor was Loki trying to shore up his credibility as Odin's son after finding out that he biologically wasn't; he killed his biological father in protection of his adopted father, shouting his name as Odinson in the process. Knowing full well -- as the audience had been previously told -- that Odin knows what's going on around him as he sleeps.

It was manipulative as all hell, as ALL hell, but the idea was not to have Odin killed. It was to put himself into Odin's favour through action, to claim him as father as publicly as possible while confirming to Odin that Loki chose him.

And it would have worked, too, if it wasn't for that pesky Thunderer. You know, not dying and staying exiled on earth like he was "supposed to". Good planning, Loki. Good planning.