The bees may need more air than just a couple of holes punched in the lid. They can also be sensitive to whatever was in the container before they were. I've had the best luck with a canning jar with a piece of beeswax for them to climb on. But I replaced the metal lid with the plastic screening that you can find in a craft store. I would put drops of honey and some water on the grid for them to eat. They don't need a lot when they are confined, and if their stomach is full of honey, they can't sting you very well. I've kept bees inside my house for more than 10 days this way. You can also find an apitherapy box on ebay, which allows them a little more room. I copied the design and built my own. I'll try and get some pictures posted for you.
Like Radar said, it's best if you can keep your own hive for the "freshest bees". The bee stings are different based on what time of year and which bee you happen to get. I've been doing BVT since last fall with some good success.
There is also a product called a pseudo queen, which is QMP pheramone, that mimics a queen for the bees. You can buy it at Mann Lake, and there is actually someone who ships apitherapy boxes that uses it in his boxes. Only if there is a real queen (or fake queen scent) in your box will your bees return to your box. (and most likely not since there is no brood or honey stores). Northern bees can go for weeks without a cleansing flight, so you might be able to get 14-20 days out of your bees if you minimally feed them and keep them cool.