Walters managed to snap off a shot, but his target disappeared.
He kept on looking, too, until the target disappeared again.
The second target disappeared from radar, but it is not known whether she sank or escaped.
Twenty seconds, then the system goes back to normal until another target disappears.
The target disappeared below ground, and at once the dummy came up in its place.
One target disappeared, and a large explosion took place at another.
Those on the bridge saw the target disappear within a minute.
However, any Doppler shift would make the target disappear.
Here, two black targets sailed straight up and overhead into the sun and disappeared.
Before I could shoot it, though, my targets had disappeared inside the bus.