D.N.
My daughter would have that problem when she was in pre-k and kindergarten also on the rare occassion in 1st grade. She waited until the very last second to go to the bathroom. She just did not want to stop what she was doing. She still does that but no leaking since she can control it more now.
Also, if she is a really deep sleeper at this point, she will not wake up to go to the bathroom at night since the signals are not strong enough yet. One of the key issues with bed-wetters is how deep they sleep or lack of sleep. My son was like this.