In the manga, Mikasa and Eren don't get together. The focus is more on the larger story and their individual growth and struggles rather than a romantic connection between them.
Mikasa loves Eren without a doubt. This is evident in various scenes and her constant concern and protectiveness towards him. It's a key aspect of their relationship in the manga.
Yes. This event occurs as a significant plot development and has a major impact on the story. Mikasa's action is driven by complex emotions and circumstances within the narrative.