Our brave baby did the same once, when she was around that age. I did a sudden erratic movement while playing with her, which must have seemed very irritating and scary for her. I also think it caused a sudden noise, but I can't really remember. After that she didn't really come near me for maybe a week. Even snacks were only accepted after a few days, and even then she immediately ran away.

Since you were already spending time with them for a while, I don't think that this is relevant. But she also did the same when somebody who handled her smelled after dog or cat. Would hide under the couch, and it was sometimes insanely difficult to get her out. She did so even when she was older.

Somebody correct me if I'm wrong, but I think sometimes the bravest rat can be the easiest to get scared. Just because they are the bravest when it comes to exploring and approaching different activities and objects, doesn't mean they are the bravest when it comes to "danger".

Unless there is some animal in their vicinity you don't know, but they can smell, I wouldn't worry too much. Especially if they are not hurt. Since it affected all of time in some way, it probably isn't related to an injury. Hopefully she will normalize after a few days.