Gerrit would follow up on Those Left Behind, but with how things ended between Titania and him this could be a disaster or the beginning of a really charming Moonlighting situation.. So yeah, if there's a mediator present he'll go.
If Shenanigans is okay with it, Gerrit would also study the diary (in a glimpse, during TLB2 or even instead) - don't wanna miss important things (or have your preparations go to waste).