Provided they cannot make contact with anything metallic and that the ends do not make contact with other batteries, you are probably fine as a sitting battery is unlikely to just explode randomly. Explosions are most common when charging, generally occurring due to overcharging. The only thing is that the box is wooden, and a lithium explosion would probably ignite the box as lithium explosions are violent. Again, an explosion from a sitting battery it is (very) unlikely, especially if they are in working order and not overcharged. I personally do not store them in a charging bag or containment box, but instead in a small battery box. If they were to explode, they would probably light the stuff on my desk on fire...however, I am not really concerned about this given the AW IMRs are very solid designs and I am confident they are not overcharged. So I wouldn't let this scare you, but act as a heads up of the unlikely, but possible.