How blocks are created and broadcast?
It would first have to broadcast the first block. The way it works, the hash of the first block (including the nonce that is needed to solve the puzzle) would included in the second block. So the miner can't create the next block without first solving the puzzle for the first block because that's the only way to get that nonce.

So you can't work on two blocks and broadcast them simultaneously. The blockchain defeats that (that nonce which you can't tell till you have actually solved the block). You can work on two blocks to find the next block faster (although I doubt it's really reasonable since you have two split your hashing power between the workloads).

Now it's possible to broadcast the first block and find the next one  or two in quick succession. This happens. Finding the hash is brute force. It's a game of probability, which is basically just a fancy word for chance.