The key difference in their attack methods right now is that Thor is scarcely trying to defend himself from blows. Bruce successfully slashes at him, but it doesn't urge him away. He presses forward as best he can, his free hand snapping forward to grab at the fabric of his shirt so he can steady him. The sound he makes is damn near inhuman, it's a low, desperate growl of pain and impatience. He has no desire to draw this out, it seems, his arm moves back and forth rapidly as he tries once more to stab at whatever part of Bruce he can reach.

He's certainly removed the knife, only so he can try to bury it elsewhere. This is the opposite of a fun game of hide the knife for anyone involved.