This is the point where Tomb Raider starts to utilize more of the tropes from standard Hollywood action movies.
The game has an interesting, yet appropriate and subtle, tone shift either at around this point or slightly before it. In the very beginning, Tomb Raider takes queues from classic survival stories. We see how this heroine and her ragtag bunch of misfits learn to use the environment they find themselves in to stay alive. Inspiration is drawn from shows like Lost (the first season), and other media of that ilk.
Then, in the middle of the game, the tone shifts somewhat. The more "comfortable" (for lack of a better word) Lara grows with killing the people coming after her and doing what she has to in order to survive, the writers stop relying on those kind of survival stories for inspiration. Because we've already seen how Lara can survive, we no longer need any further evidence of it.
For that reason, Tomb Raider is now free, in this last half of the game, to go the route of more pulpy, adventurous stories in the vein of Uncharted and the Indiana Jones films that they are clearly dedicated to. These stories rely much more on spectacle and flare. Details can be left unexplained if they are not relevant to the broader arc, and action takes the day.
I stand by what I said in the episode about the shift being a little abrupt, but I understand what they were trying to do. This was always marketed as an origin story to take a relatively normal girl and transform her into something resembling the Lara Croft we knew from the other Tomb Raider series. Simply put, no one could possibly becomes that hardened without under great ordeals, so this second half is meant to give Lara the ability to overcome adversity. She's already a survivor, but now she can turn herself into a hero. It's not a bad idea, it just needed some slight changes to get right.