You shouldn't feel bad. A few days in a dark box is not that big a deal. Heck, mine spend days on end burried in dark holes, and they do that to themselves. In fact, since mine all came up from hibernation too soon because of this crazy weather, I have had them in a 3 x 2 plastic tub under the box turtle table. They spend their days basking, eating and stinking up the entire house, lol. They will be as happy as I will be when I can put them back in the garden but they aren't in any danger from the temporary housing arrangement. And none of my 26 turtles and tortoises relax in the tub. They all run around like they are being dipped in acid. It is great exercise for them since they are cramped up in their winter homes. Keep the water warm to the touch, not to hot, not to cold and let him go at it. It is like running on a tread mill. It can only help the little guy.