Maybe something like this was used
The combination of the two would actually allow responsible time travel. Send something like Kilm people/probes back in time to rescue a few dinosarurs and early mammals.
Now wait, you say--we might take the early mammal that evolved into us.
The solution, take the mammals scan when the probe returns--protect the data in a shield, and hit the probe with the weapon ships beam. Time line restored, and the info is still there.
Something similar is how the Doctor escaped--but he is forever locked out...