Fledgling collared dove in warehouse!

I wonder if anyone could advise.  I reslise there is a lot of advice about fledgling birds, but feel this situation is a little different.

We have a collared dove (I think) in out warehouse at work.  It's sibling has already died I'm afraid :(  so I was wondering what was best to do with this one.  The parents hve been in our warehouse for a while, building their nest etc (there is a hole in the roof where they can get in quite easily.)

The thing is, at first it was on a large ledge up high out of the way.  But it decided today to make it's way to the floor and stay there.  Bossed at work either wanted to kill it or put it outside.  They said it was doing its mess everywhere, and was going to get injured in a busy warehouse anyway.

Well I certainly was not going to let them kill it, and was worried that the parent wouldn't find it again if it was put outside.  So in the end I caught it in a box and put it back on the ledge where it was, out of the way of danger.

I am a little worried that when we go back to work tomorrow it will bw on the floor again.  Anyone have any advice on the best way to handle this?  Obviously because it isn't outside already, it would have to find it;s way out of a hole in the roof to get out!

I am trying to give the little fella as much of a chance as possible, so any advice would be greatly recieved.