The vending machine might not be out of place, I just can't tell what kind of overall environment is going on here. I don't know what's beyond those doors, so I can't make a call like that. It might just be a rest area within a more industrial setting. I've no idea. But it does look odd there, and it's way too thin. You shouldn't back it up to a staircase with the top half of the backside exposed like that. It looks like a meaningless prefab totally just thrown in there because you needed to liven up the area. If you decide that it actually belongs in its current setting, then build a recess into one of the nearby walls and house it in there along with maybe a trashcan and shit like that so it doesn't look like it fell out of the sky.
I also recommend spicing up the cradle structures that those tanks are resting in. They look kinda odd and blocky right now. But then again, that might fall in line with the rest of the architecture if you're shooting for a very Half-Life-esque feel.
and collapse is right, you need light fixtures even if there's no light emitting from them. I can't think of a single situation where a room would be left intentionally unlit in a facility like that.
I'd say you need more signage and little superfluous details like that (fire extinguishers, alarms etc.) And vents. I love me some vents. Floor drains never hurt either.
The thing is, I don't feel that a little room like this is all that deserving of intense critical analysis, since it will probably only be seen by the player for a matter of seconds as they walk through it. It's not the kind of major area I'd stress about. But aside from the base architecture it is kinda bland at the moment.
EDIT: Looking at the screenshots, a more overall criticism I can give of the architecture in The Core is that it is overwhelmingly square. Refreshingly, this room doesn't suffer from that, but most everything on the ModDB page is just so... boxy, clean cut. Like you took an empty box and then added a bunch of pretty details to it, but it's still just a dressed up box. Very realistic, I suppose. But the eye needs more variation. I can only assume that what you have up there is not an accurate representation of the mod as a whole, but more likely a lot of pictures of a few select areas and that's just the architectural style you were going for there. But if it is, well, you might want to change things up.