What I took away from this preview is that Thunderbird 4 will be getting some much needed screen-time since she has not been used sin the Ring of Fire.
The little to no action that IR's mini-sub has received is almost akin to the relegation of action that John received in the original series. Which is a shame as the 2015 incarnation of Thunderbird 4 showed a lot of potential for the underwater rescues it could perform with the features of rescue pods and grappling arms from it's main body.
I like the Easter Egg nod to the Crab-logger from Path of Destruction. I find it interesting that a toxic-waste transporter would "drive" on the seabed. I don't know the specifics as to how that would be achieved so I'll just leave that be.
In recent episodes the writers have been able to take the suspense factor to a point where the team have to had to use a new approach to successfully complete a rescue that you don't know if each use will work.
Take last week's Skyhook for example where we thought that Thunderbird 2 would be able to complete it but had to withdraw due to the lack of electrical dampers on the weather station, which then followed with Thunderbirds 1 & 3 respectively attempting rescues and ultimately failing due to Langstrom cutting corners that it was left up to Thunderbird 5 to act as a rescue craft, which might I add, had never been done in the original series.
If the show can knock it out of the park again with Under Pressure then it just shows the consistency that has been put into the writing and production of this Generation.