Bob, I haven't played Time Machine, but I'll quote from a walkthrough here at GameBoomers. I hope maybe it will help you....SPOILER
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
"Stay on the platform, and use the Chronoeider to shoot the Lemurs. If you were efficient in closing the gates, there will only be three. There may be more if you were slow, but it doesn't matter. Some of them will probably hang back near the gates, and will be hard to see until you step forward a little. As long as you stay on the top step, they can't hurt you."