Here is how Shaw unleashes a Kaiju and Selene and some others switch sides goes in Pooh's Adventures of The Myth of Burton.
(we see the Club and Villains preparing to take the Phoenix Force when we hear Nighlock's voice)
Nighlock: Your days of tyranny are over Shaw and villains. Game over. Surrender now.
(They see Thomas the Tank Engine and his friends from Sodor arrive)
Sebastian Shaw:(turns to a soldier) Release the Kaiju. So these traitors the meaning of pain.
Thomas the Tank Engine: Oh, no you don't. (fires his gattling guns)
Donald Pierce:(forms an energy shield around the soldier)
Sebastian Shaw:(steps in front of the shield and abosorb so the impact of the bullets and a missile)
Nighlock:(tries to stop them but too late) No don't!!!
Thomas the Tank Engine: Don't worry! We've got everything under control.
Blob:(tackles him) You idiot! Don't you know he can absorb kinetic energy?!
(the explosion of the missile shrinks and Shaw is revealed to have absorbed its energy)
Flynn the Fire Engine: I'll handle this!
Sebastian Shaw:(stomps on the ground causing an explosion that knocks out Flynn, Percy, and Gordon, while watching the explosion circle around everyone)
The Grand Duke of Owls:(laughs)
Thomas the Tank Engine: Flynn! Percy! Gordon! Everyone!
Angel:(with wings in fighting stance) You'll pay for that one Shaw.(charges)
Jafar:(fires a blast at him)Down boy.(which knocks him out of the sky)
(Due to the delay the soldier released the Kaiju and it attacked the two agents, mutants, and heroes)
Indominus Rex:(transforms into her true form and fights back)
Nighlock:(begins healing him)
Percy: Thanks that feels so good.
Nighlock: You're welcome.
(as Indominus charges, the Kaiju swats her away)
Kaiju:(turns towards them, and prepares to eat them)
Indominus Rex: Roooaaar!(begins transforming)
Nighlock:(covers his mouth) Don't say it. If you say it, something bad will happen.
Toad:(in Pinkie Pie's voice) Okay.
Indominus Rex:(attacks the Kaiju and rips its throat out)
Sebastian Shaw: Hm. I'd thought this would be a bigger challenge.
Selene:(punches him) What was that all about?! You just unleashed our monster on our own kind. I thought mutants don't kill mutants.
Sebastian Shaw: We don't.(brushes his shoulder off) We just kill the ones who won't join us.
Selene:(shakes her head in anger) I can't believe I trusted you.(walks over to everyone and helps heal their wounded) Whoever is willing to join me is welcome.
Harry Leland:(walks over to her and uses his medical training to help)
Empath:(walks over to them and makes sure Thomas is okay)
Tarrot:(joins them and punches Thunderbird in the face)
Catseye:(picks up Angel and takes him to Nighlock to be healed)
Spinosaurus:(picks up Indominus(in human form)and sets her down next to Scarlet Witch)