Referencing that comment about snagging them to the middle--I know this is just a thought experiment, but I would be more that can be a pretty brutal way to die. There was a story about some guy who was trying to show off to his friends by lying under the train as it passed over him--hooks on the bottom of his train got caught onto his jaw and well... that was the end of that.
As for the question, I probably wouldn't save my loved one thinking about it atm. In the heat of the moment I might save them because my emotions would be pretty frazzled, but to put myself in their shoes--I wouldn't want to live knowing that my life was saved at the direct expense of many others. To the best of my knowledge, the few loved ones I have would all rather die than live having others die for them, and I would want to spare them from a miserable life.
Now, if I could kill all those people without my loved one knowing about It, I would probably just save my loved one lol