Visible crew/equipment: When Alexander hears the child scream a foreign language and hears others, he looks down. As the others are climbing up the ropes and ladders, a safety strap "KEEPER" is seen holding one of the platforms up.
Visible crew/equipment: In the widescreen version, when Alexander stops his time machine in the year 2030, he lowers the steps to get off. As he's doing this you can see the reflection of a few crew members in the pressure gauge located by the steps. (00:28:00 - 00:28:55)
Answer: When Alexander is travelling through time, he sees everything in his lab being removed very quickly, so the equations on his board were most likely erased and his journals were probably thrown away.