We were asleep and woke up horrified by the blast.

She may have fallen asleep on the bus. When she woke up, she made herself known to someone there.

I only remember that I was asleep and when I woke up, the van was already turning over. When the van stopped, I was thrown into the grass. I turned my head, and saw that other people had been thrown out. I couldn't see whether they were OK. I couldn't move. I couldn't sit up. I couldn't walk. All I could do was wait for help to come. It seemed like forever because of the pain.

I had a dream that I was awake and I woke up to find myself asleep.

I'm horrified,

I was horrified,