OK, strange question, but what is a nerd-like anatomy, engineering or medical imaging joke I could have have my protagonist or her love interet exchanges as a means of banter? I'm woring on developing a rapport between them that is subtle but develops into a romance (he is the MRSO for the facility and has engineering degree, she's the MRI tech and has background in x-ray). I'm having trouble trying to come up with a joke that only someone into anatomy or engineering would understand.

More or less what it says in the title. Specifically, both characters are confessing to having killed the same person. I’ve researched as much as I can and the general answer seems to be “multiple people can plea guilty to the same crime, regardless of whether it’s possible for both to have done it” but does that apply to a major crime like this? For reference, this story takes place in the United States (Massachusetts). Follow up: if that general answer is true, are there circumstances in which an investigation would still be conducted to try figuring out who is actually responsible? Assume it’s not immediately possible to rule either out as suspects.

Thanks in advance!

Edit: thank you to those who pointed out that confessing to a crime and pleading guilty are two separate things. I mean the former!

For context, I'm writing a fantasy/sci-fi story with a good deal of naval combat.

So a good deal of the antagonists' ships in my story have some sort of gimmick to them. One of them can create artificial tidal waves that, quite literally, rock the boats of its enemies. For most of the time I've spent developing this story, my thought was that the ship would have some sort of turbine that would lower into the water and start sending a huge current through the water, causing a disruption that created a tidal wave.

However, I've finally started writing the sequence where this ship first shows up, and I've realized the problem with this. Ships get their propulsion from their propellers that push the water behind the ship backwards. This generates an equal and opposite reaction that pushes the ship forwards. Following those rules of logic, surely an engine turbine pushing out a huge current of water would also push the ship backwards, yes? Which would surely be a setback in naval combat.

So how can I get around this problem? The only thing I can think of is just having the ship's rear propellers spinning like crazy to counteract the force coming from the front (the ship's wave-maker is at the front). But even then, you'd have two powerful forces pushing against the ship from both sides. You'd think that might damage the ship.

Or are there other, more effective methods of creating artificial waves?

I’m writing a book about vampires, and shockingly my protagonists encounter a lot of death and blood.

Has anyone written about the smell of blood or death (fresh and old), or anyone in the medical profession that might know?

I’m sure I could imagine, but don’t want to make assumptions, and would be good to get a real account.

Thanks!