Shelves aren’t really a necessity on a secret government facility hallway.
Since shelves would most likely not get used in a hallway, They would also not provide and help at all unless you want to sneak something out.
So shelves would most likely be placed in rooms rather than hallways.
Same with flowers, a secret government facility that houses dangerous anomalies would probably get used to hide certain information in it.
Pallets would be useless in a setting like this since I doubt the SCP Foundation would waste budget on decorations.
In a real life scenario It’ll probably only have a number to either the right side or left side of the wall to indicate what hallway it is.
And a few cameras and a map.
Even though it looks boring this is what a real secret hallway would look like. Since that is what OP is going for.
I agree with texturing it looks bland, Adding tiled floors and a few stains on the walls would make it less bland.