By “indicators” I assume you mean left/right turn signals.
After the car pulled over to the side of the road, did you try using your hazard lights? If so, did they work?
If the Hazards have not been tested and/or do not work, then it is possible that a fuse has blown, possibly due to a fault in the rental trailer’s wiring.
I don’t have documentation for 2010 that would apply to Outbacks sold outside of North America. However, on North American models, the fuse that powers the Hazards also powers part of the Shift Lock control system. The shifter lock control is what allows or prevents the shift lever on the center console from moving from Neutral to Reverse and then to Park, as well as when moving out of Park. So there is this common factor.
On our 2010 Outbacks, it’s fuse #18, 15 Amp, in the engine compartment fuse box. This fuse is always on, even when the ignition switch is off and the key is removed. The fuse is identified in the Specifications section of the Owners Manual as being for “Roll and hazard warning flasher (body control unit)”. It may be the same or similar in your manual.
I hope this helps. Let us know if that was the case and if not, what other fault was found.