only if the entire arena was full of boxes. it's more likely that just a small room would have less than 10 boxes in a pile and having solid brushes in them to prevent players, especially non-spies, from hiding in them
I was thinking more the entire map being filled with boxes. Not that anybody would nominate a map that isn't shitty weapons depot or military area. *Crevice is bae*
 
if there's a trigger to start the beacon and start draining their health, I'm all-in-all for it (e.g. 20 secs).