He won't pursue it, but he will keep menacing it until it goes away entirely.

It crawls off back into the undergrowth not actually seeming to react to Sura waving his sword around it's just not interested in them anymore, looks a lot less scary with all its pointy spines retracted.

"Glimmer?"

"Yeah I see her Bow, or...him"

"Okay, I wanted to make sure it wasn't just me seeing the prisoner turn into a SWORD PRINCESS!"

"HOW DID YOU TURN INTO A PRINCESS?!? THAT WAS AMAZING!" There are many a happy excited squeal coming from Bow.

"I told you it was my sword."

And then - 

He doesn't feel like he's in danger anymore, nor like he needs to protect the idiot rebels who captured him.

He shimmers, and suddenly he's a lot shorter and the sword's a lot heavier.

He grunts, annoyed now.

"I don't care how he did it. We just have to make sure he never does it again!" Teleporting up to Sura and grabbing at the sword.

Annndddd now the bug is back! Apparently, Sura being a giant sword lady was what was keeping the bug monster pacified. It barrels into all three of them throwing them down a slope. The group tumbles down the slope until they stop in front of a big vine-covered temple.
Sura still has the sword, but Glimmer is too winded by the tumble to care right now, and Bow thinks the prisoner is alright in his book for saving them from the bug the first time and being a princess.

He scrambles away from the other two once he lands.

...This does not look like rebellion architecture.

"What is this place?" Glimmer stares up at the roughly pyramidal temple.

"No idea, but in there's gotta be better than out here." Bow runs up to whats clearly a door and slams against it ineffectually with a thump.

He follows, furrowing his brow at the writing. "Is it locked?"

"If you both grab on I can teleport us inside!" Yes, even the horde soldier gets to be saved, she isn't going to leave him to be eaten by a monster.

"Glimmer, no! You've never teleported three people before." When glimmer overstresses her magic it ends...badly. Bow doesn't want Glimmer to hurt herself trying.

"Do you have a better idea?" She snaps back.

The ground rumbles and the roar of the bug monster can be heard, it's not done with them yet! They can see it slowly pick its way down the slope towards them, having to be careful because of its size.

"The writing on the door - might be a clue to opening it - "

It's a long shot, but...

He also tries flinging himself back in the mindset he'd been in earlier. It's tricky, doesn't really work just yet - does he need to see someone injured? -

"It's first one's writing, nobody can read that writing without like a zillion degrees. now hurry up and grab on if you don't want to be bug food!"

"What? It says 'Eternia' - "

And the door rumbles open.

"OH COME ON!" Glimmer throws up her hands in frustration. First, the prisoner can transform into a really tall sword princess and now he can read first ones writing?!

They all hurry inside, the bug can't get in the door opening it is too small. Safe for now but the only way on is inward.

After they've all walked down the hallway a while...

"So, Horde soldier, have you always been able to read First One's writing?" Bow asks casually.

"Wanna tell us what exactly is going on here?" Glimmer staring at the prisoner who still had the magic princess sword and was not tied up in any way. This was so weird to be casually walking with them.

"I haven't seen it before. And I had a vision of the sword, and a glowing woman. Light Hope. She said the sword was mine, and Etheria needed me."

"That is so cool! You got like an actual call to adventure! You get to be a princess! why don't I get to be a princess? literally everyone I know is a princess even the horde soldier! it's unfair." Bow is starting to ramble a little bit, its a stress response and he was just almost eaten by a big bug. Twice.

Glimmer doesn't look like she believes Sura but doesn't say anything, he did just save them. She's not a jerk, even if that boy is still literally part of the evil horde.

"I'm not royalty."

"You transformed into a tall warrior lady wearing a tiara using a magic sword that radiates the signals of first one's tech. plus like Netossa and Spinerella are princesses that we know and they don't rule anyone. Glimmer do they rule anyone?"

"No." And Glimmer keeps on walking.

After they walk for a while with Glimmer in front, Bow sidles up to Sura.  "Thanks for saving us anyway. I'm Bow, by the way."