The way I've always seen it, Nick Fury has always held the safety of the US/Planet/whathaveyou above all else. If the only way to stop an impending invasion and complete distruction of the US is to lie to the only people he knows can stop them, he would do it without hesitation. He's not out to make friends and drinking buddies, he's doing his job. He had no problem firing an RPG at that jet to stop it from dropping a nuke, even if it meant killing his own men.
Mjolnir is kind of tricky. I mean you could say it becomes heavy because Hulk was unable to lift the hammer, but thor used Mjolnir to pin Loki to the Bifrost and it didn't kill him. I mean if it became immensely heavy, in theory it could of killed Loki since Ashardians arent immortal. Also if it was immensely heavy, it would of sunk into the mud instead of bein held up by the mud pile.
I like to think that the hammer is very heavy, and only someone with superhuman strength could wield it. If the hammer is on the ground, then it cannot be moved by anyone period. If the hammer were to say land somewhere with a sharp angle or drop, it would fall due to gravity until it landed on a flat surface.
pff that one almost killed me haha:facepalm
