Running through a frozen Hallway

"I was running down a hallway that looked like my apartment building, except it kept stretching longer the more I moved. I knew I was late for something, though I couldn't remember what. My legs were moving fast, but the walls barely passed me, like I was running on a treadmill that kept speeding up. I tried to grab the railing to pull myself forward, but my hands went right through it. At one point I looked down and my feet weren't touching the floor, just hovering slightly above it while I kept making running motions. That made me panic more than anything else. Then I was outside, still running, but everything around me was frozen—people mid-step, a dog in the air, a car stopped halfway through an intersection. I yelled for someone to help, but no sound came out. I woke up with my heart racing and my legs all tense, like I'd actually been trying to run in bed."