Here's how Anck-su-namun kills Evyeln and Thomas saves Celestia in Thomas, Twilight, and The Mummy Returns.
Eveyln: [sees something] Rick.
[The sun is rising]
Rick: Let's go, Alex! [grabs his hand]
[They all start raicing to the pyramid]
Rick: Run! Come on, Alex, faster! Come on! Come on!
Alex: Dad, the bracelet!
Rick: Run! Come on! [picks him up]
[They raced to the pyramid, just in time!]
Rick and Alex: [panting]
Rick: You know? It's not, easy being a dad.
Alex: Yeah, but you do it really good.
[The bracelet detaches and Alex throws it, and the rest of the group comes up]
Eveyln: They made it. Thank God.
Johnathan: Oh, yes. Great. Fabulous.
[But unknown to them, the villains came up]
Queen Chrysalis: See, what I tell ya? He lead us right to them!
[Anck-su-namun stabs Eveyln!]
Imhotep: [throws Johnatahn]
Rick: Evy! Evy! Johnathan! Johnathan!
Alex: Mom! You're going to be all right isn't she, dad?
Rick: She'll be fine.
Alex: She's going to be all right?
Rick: Just get him. Take him. Take.. Mommy's fine. It's okay.
Megatron: Now to finish you off, Celestia.
Princess Celestia: You wouldn't dare!
Megatron: Oh, yes I will. [he takes out his shotgun and points it at Celestia] You're so weak!
Thomas: [is just racing into view and sees his mentor about to be killed] NO!
[Celestia turn her head away and shuts her eyes prepared for the worst]
Megatron: [cocks his shotgun and fires]
Thomas: [drives in front of Celestia at the last second and is hit] (as Optimus) AAAAAAAAAAAAAHHHHHHHHHHHH!!!!!!! [he tumbles over cab over wheels]
Princess Celestia: [opens her eyes and her jaw drops as he sees her student tumble]
Rick O'Connell: [looks toward them when he hears the blast]
Twilight: [looks back and her jaw drops at the sight]
Megatron: [put his shotgun away]
Thomas: [tumbles over a feet more feet and then lands on his side]
Cadance: NO! THOMAS!
Percy: Oh no, Megatron got Thomas!
Johnathan: Your mother's gonna be fine, okay?
Rick: Oh, my God! You're real strong, you're going to make it, you're going to make it. You're fine. What do I do? What do I do, Evy? What do I do?
Eveyln: Take care of Alex.
Rick: No. Sweetheart, no.
Eveyln: I love you. [she slowly dies]
Rick: No, don't... No, no! Evy? Evy? No, no, Evy! [cries] Come back, Evy. Evy, come back. Come back. [cries]
Thomas: [groans] Guys, run.
[then Thomas slowly shuts his eyes and is now gone]
Willy: [looks close at Thomas] I'm afraid.... he's a goner.