If you want to intervene, then delay doing so a bit. Have them taken prisoner. Have them held on the ISD and have it report that they suspect they might be Force-users. Have the Inquisition request they be transported to Prison Location X where the Inquisitor will see them. The ISD has it's own mission, so they are sent on a Shuttle. Unknown to the Imperials, a Rebel spy aboard the ISD has sent word out that a party of "maybe Jedi" has been found, and the Rebels plan to intercept the shuttle before it can deliver the prisoners to the Inquisition...
All of the above is narrated at the beginning of your next session in the "opening crawl" and now play begins as the Rebels ambush the shuttle.