Dockatot in Bassinet

So my sweet little boy decided he hates our Halo Bassinest, and as soon as we put him in it to sleep at night he starts shrieking. I keep reading reviews and watching YouTube videos about the Dockatot, and it seems like people and babies absolutely love them. 
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I'm thinking about getting one to help my baby sleep at night, but we have a queen size bed and if I put it in the bed my husband will have to sleep in our guest bedroom. I considered putting it in the Bassinest (or Pack n Play), but the Dockatot website advises against this. 
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Anyone know why? It seems to me that if it fit snugly in the Bassinest it would be safe. I'm just at my wit's end trying to help my baby sleep at night.