they saw.

Mark 9:8
Suddenly, when they looked around, they saw no one with them except Jesus.

Luke 9:36
After the voice had spoken, only Jesus was present with them. The disciples kept this to themselves, and in those days they did not tell anyone what they had seen.

Acts 12:10, 11
They passed the first and second guards and came to the iron gate leading to the city, which opened for them by itself. When they had gone outside and walked the length of one block, the angel suddenly left him. . . .