Read this excerpt from Little Brother and answer the following questions in complete sentences using proper grammar and punctuation: Marcus manages to flag down a vehicle and they get more than they bargained for... It was a military-looking Jeep, like an armored Hummer, only it didn't have any military insignia on it. The car skidded to a stop just in front of me, and I jumped back and lost my balance and ended up on the road. I felt the doors open near me, and then saw a confusion of booted feet moving close by. I looked up and saw a bunch of military-looking guys in coveralls, holding big, bulky rifles and wearing hooded gas masks with tinted face-plates. I barely had time to register them before those rifles were pointed at me. I'd never looked down the barrel of a gun before, but everything you've heard about the experience is true. You freeze where you are, time stops, and your heart thunders in your ears. I opened my mouth, then shut it, then, very slowly, I held my hands up in front of me. The faceless, eyeless armed man above me kept his gun very level. I didn't even breathe. Van was screaming something and Jolu was shouting and I looked at them for a second and that was when someone put a coarse sack over my head and cinched it tight around my windpipe, so quick and so fiercely I barely had time to gasp before it was locked on me. I was pushed roughly but dispassionately onto my stomach and something went twice around my wrists and then tightened up as well, feeling like baling wire and biting cruelly. I cried out and my own voice was muffled by the hood. I was in total darkness now and I strained my ears to hear what was going on with my friends. I heard them shouting through the muffling canvas of the bag, and then I was being impersonally hauled to my feet by my wrists, my arms wrenched up behind my back, my shoulders screaming. I stumbled some, then a hand pushed my head down and I was inside the Hummer. More bodies were roughly shoved in beside me. "Guys?" I shouted, and earned a hard thump on my head for my trouble. I heard Jolu respond, then felt the thump he was dealt, too. My head rang like a gong. "Hey," I said to the soldiers. "Hey, listen! We're just high school students. I wanted to flag you down because my friend was bleeding. Someone stabbed him." I had no idea how much of this was making it through the muffling bag. I kept talking. "Listen—this is some kind of misunderstanding. We've got to get my friend to a hospital—" Someone went upside my head again. It felt like they used a baton or something—it was harder than anyone had ever hit me in the head before. My eyes swam and watered and I literally couldn't breathe through the pain. A moment later, I caught my breath, but I didn't say anything. I'd learned my lesson.
In three to five sentences, summarize the conflict Marcus is facing in this excerpt