To be happy or not to be happy

So Elliot is pretty much potty-trained. He'll only go in his pants when we've been out in the car too long without letting him go, or if Eric and I are fighting - which is great incentive to not fight! (Not that we fight a lot, but you know what I mean.) So here we are all proud of our son, happy we aren't buying diapers as much, and pretty amazed at the whole thing. This is a good thing, right? Well in the last three days during either a nap or bed time, he's pulled off his pants (good to know he can do that now!) and figured out how to take off his diaper (which he still wears when he sleeps) and pees on his bed or OUT his bed onto the floor! OMG! It's really frustrating! It's weird through because he keeps telling us what he did and is really kinda sad that it's happened. So we think he is trying to be really good and NOT go potty in his pants like we've told him. We think he's taking off his pants but there is no potty around, so he just goes there.... but it's not in his pants, so it's okay right? How do I explain this to a 22 month old? Good grief! Just in case anyone else has gone through this, we'd love some input! :)