Tilly is the most lovable engineer I've seen in the ST universe. For some reason she can sleep happily, even snore while Michael is screaming her lungs out at the end of result of seeing a hyper dream. Maybe she psychically connected with the Tardigrades, and it was showing our beloved scientist how it's feeling for being kept in captivity at the hold of a starship.
It cannot be a nice place to live, when you're used to churn all days long something else than a force field. Discovery's scientist, Michael including aren't taking in account the fact that the ship is making things sick despite measurements. The other one had gone mad after it got taste to Klingon flesh.
If they hadn't messed up with the business, maybe together they could have figured out this cosmic creature rather losing Ripper to the universe as Alexa said it. Maybe we have to give thanks to the fish and accept the fact that there's life in the endless space. Maybe more so than we'd like to accept at the moment. After all it is infinite and when you approach that number the magic start to happen.
Sporedrive is ultratechnology and it shouldn't be allowed, because it breaks boundaries. Yet, we humans explore the impossible every moment. It is almost as the Captain Kirk said it: "To boldly go, where no man has gone before." With the sporedrive they could have broken the rules and the history of ST universe.
What have got broken are meeting the larger than life characters in the same place. Always in trouble, and always causing mayhem wherever they appear. I hope they really blow life through Harry Mutt's character and show that there is no paradise waiting for us whenever we get over there. It is more likely that the life follows the same cycle as we've witnessed over the eons in the human society.
All we know is that we are a brutal race. Far from ideal for bringing everlasting peace in the galaxy. In fact, Captain Lorka showed a level of violence that's true to these types of conflicts. He didn't even bat an eyelid for burning half of captain's face off with plasma fire. Although I have to say she was very lucky that it wasn't direct hit, because it would have ended badly.
At the end of the day life wins in the ST universe. In my opinion it's not the mirror universe.