I know exactly how you feel. I just went through something very similar.

I rescued a chinchilla a couple of months ago. I had him a week, when he escaped from his cage. He chewed through a plastic tie holding his dust bath house onto the door opening. I never thought about it, I suppose, just having gotten him and the cage. He got out during the night, and squeezed right under the baby gate seperating the living room from the kitchen. (The chinchilla and the birds were in the living room, and the dogs in the kitchen, just for safety's sake. So where does he go first thing ... under the gate!)

Of course, the dogs killed him, in about 30 seconds. I know he didn't have a clue what hit him, because he didn't make a sound, and there wasn't a mark on him. But still .... I cried and cried and cried. This innocent little creature depended on me to keep him safe, and I let him get killed. It's VERY hard. I know what you're going through, and I'm very sorry.