Vidar: He didn't do anything on Asgard he left which means he failed. Whether he returns is another story, for now my people are at peace. Remember once we have the time matrix we can go back to the time before he found it. We stop him again before he get hold of the time matrix. Then he will no longer be able make the changes.
Look at it this way if I go back in time and kill myself, I would no longer exist in the future. Because of that I wouldn't be able to go back in time to kill myself, as such time would remain unchanged.
Odin: It doesn't matter, we need to stop Ken'atra, the sooner the better. When we stop him we will then posses the time matrix.
Now if you don't mind we can continue this debate another time. We are here to stop Ken'atra, and acquire the time matrix. Now if you please, either be quite or say something that will help us accomplish our goal and get back home.
"Dulce bellum inexpertis."
Official Forum Expert on Norse Mythology
As Odin says in the Hovamal:
"Praise no day 'til evening; no wife 'til on her pyre; no sword 'til tested;
no maid 'til bedded; no ice 'til crossed;
no ale 'til drunk."