Suggestions needed: Avoiding Il Dracon de Mer [Digging for Lies]

So my group totally avoid the smuggler's naval encounter in Skyseer...and they are on the verge of again avoiding this battle too.

They pulled there ship a relatively far distance away, waited til nightfall and slipped in the water. I'd say tough to detect from the Dracon. They intend on swimming directly to the dig site (they used a Water Breathing ritual).

The adventure says "It's not safe to go after Caius's team before dealing with the hostile vessel" - but why? I told the PC's they've got a crew of 30, so they want to avoid it now. Obviously, they're in for a big fight underwater here, with Caius's team, the elemental + any surface help. But I'm stuck on what exactly the thread of the Dracon topside is...and why it was such a priority to eliminate first.

Commotion at the site will certainly alert the crew...should all of them dive in? The captain won't leave his ship, for sure. Or...will it engage after the PC's return to their ship? Should it attack the Dagger, Inspiration, and the 2 Allied Officers the PC's left on their cutter?

Ideas here? Once a DM announces "30 crew", the PCs are likely going to avoid altogether.

You're a mercenary captain who has been hired to protect a group while they're underwater. A foreign ship shows up, and then odd things start happening underwater. What do you do?

You sink the foreign ship.

So when the party gets back to the surface, the vessel they came in on is a smoking heap and the crew have surrendered so they won't be chopped up. I guess the party could swim for shore, but they'll probably have to try to claim Il Dracon de Mer for themselves. Which would've been easier if they had a ship of their own.

Right...which is what I'm afraid of. They probably defeat the enemies underwater, but then they have no ship. (BTW...Not sure about the auto death scenario of failing to close the portal. Dashed against the rocks until their dead, reroll characters?)

Anyways...they will then surface completely exposed to a crew of 30+ with likely no ability to take a short rest. And they have had to deal with the elemental as well. Their Allied Officers are likely dead. It's almost certain they get captured, don't get a ship, don't get to see Finona's letter, and get - as the module suggests - get ransomed back to Risur months later. Adventure over? Campaign over?

Perhaps they swim the half mile to shore. This assumes the Dracon sunk their ship and the Dagger and Inspiration (why would they leave them alone?) I guess Xambria gets captured...and somehow starts eating everyone on the Dracon on the way back to wherever it was going? PC's have to charter passage back to Flint somehow...man, I need to think this out a lot more.

My point is that there is a very high chance that catastrophic things happen in this sequence. Auto-TPK, capture and months out of the action, a few set pieces totally circumvented...and a complete miss of the rest of the events of the timeline. Yeah, I know I have control over the story...but I feel like I have to railroad a lot here. My Yerasol Veteran basically drooled the entire time at the "Possible Promotion" encounter (he WILL not get a promotion)...and his date pickpocketed a guest (didn't get caught). My PCs are a special bunch!

Looks like I'll be designing a prisoner breakout encounter on the ship...not sure how Xambria will escape, maybe a passing trawler.

I just ran the Dracon encounter with my group, and I have to say that the thirty or so minions are really not all that lethal if you have any area-of-effects on your team at all.

After they've cleaned up underwater, they can have a short rest by the lanterns (endless air supply), then swim up to the surface and storm the ship. Even climbing up the side, it's not like the mercenaries have a plethora of ranged weapons to pick them off with, and the cannons will be useless.

PCs kick ass, find Finona's letter, and are sailing a huge impressive ship back to Risur (or possibly hitching a ride on the Dagger, or paying a mage in Ber to teleport them back).

And the "dashed against rocks until they're dead" should really only happen if the PCs are cowardly enough to turn tail and run during the encounter, I don't think there's actually a time limit. If they *try* to run, just tell them the swirling vortex will almost certainly kill them, and I'll bet they'll turn around.

TL;DR. The whole "seal of Mavisha" thing should in no way result in a campaign-ending situation unless you let it, or unless your PCs are hell-bent on killing themselves.

I'll keep y'all posted, but so far they are in the middle of the seal battle - with the dracon off to torch their ship...and they just tripped the wards on the seal. This is a tough fight.