I wouldn’t call that hiding. Probably just securing the area until more could be learned. I don’t blame them but my inclination would have been to investigate, discover, and assist if possible.
Then again maybe they thought that lacking proper Intel on the situation the best thing to do was secure the area from a still to occur armed assault.
I can see good points in either direction. My training would tell me, secure and defend. But my habit and inclination would be, investigate, determine, and assist.
Just one of those things that would be a tough call at the moment.