Because of his horrible injuries, it's probably safe to assume that Håkan is just as loaded up on morphine as the Cancer Lady was in the novel. And when you consider that, Eli's odd reaction to drinking his blood at the hospital starts to make a little more sense.… and Eli tore her head away from the woman's throat. The blood tasted like medication. Morphine.
Eli is drugged.
Notice the strange expression on Lina's face when she suddenly pulls her head back and lets Håkan's body fall to the ground. Not only does she forget to break his neck, she doesn't do anything to make sure he's dead. She just stares down at him with a confused look on her face and drools blood all over her shirt. (The IV bag behind her is very noticeable in this shot.)
Right after this Eli flies to Oskar's room and crawls into bed naked with him. It's totally out of character for Eli to do something like that (at least with Oskar) but you have to remember that he's still under the influence of morphine. In the novel the very same thing happens right after his encounter with the Cancer Lady.
Of course I might be looking at this all wrong.


