Awaiting EIC Decision
The answer is that we can’t know. The status of the manuscript is exactly what it says on the tin - that it’s awaiting the decision of the EIC. 

Trying to divine why is a bad idea. It’s possible that the original review notice was internal, not external. It’s possible the reviewers turned things around super quickly (my personal record is a single day). You can spin up a number of “just so” stories about the status.