Character Analysis
There are two types of Star Trek fans: Those who think Montgomery Scott, a.k.a. Scotty, is the man…and those who think other fans don't love him enough.
Scotty's the chief engineer of the Enterprise, and perhaps the only person who loves the starship more than Kirk. That's because it's his job to keep the ship, well, shipshape. Just consider the scene when Admiral Morrow debriefs the Enterprise crew:
MORROW: Scott. They need your wisdom on the new Excelsior. Report there tomorrow as captain of engineering.
SCOTTY: With all appreciation, sir, I'd prefer to supervise the refit of Enterprise.
MORROW: I'm afraid that won't be necessary.
SCOTTY: But, sir…
MORROW: I'm sorry, Mr. Scott, but there will be no refit.
Just look at his face in that scene. He's visibly shaken at the prospect of losing the Enterprise—his baby—for good.
So when Kirk rallies the crew to search for Spock, he's right there to help.
Like the rest of the Enterprise crew, Scotty connects with the movie's theme of loyalty and family. Spock is a member of his family, so Scotty will give up everything to help the Vulcan if he can.
Scotty's contribution to the effort is to remove important parts from the Excelsior's transwarp computer. When the starship tries to chase the Enterprise, it breaks down right in front of Spacedock.
As Scotty puts it:
SCOTTY: The more they overthink the plumbing, the easier it is to stop up the drain. Here, Doctor, souvenirs from one surgeon to another.
Based on his smile when he delivered that line, we're guessing the conflict with the Excelsior might have been a bit more personal for him than the others.
Beat the Enterprise's speed records, Captain Styles? Not on Scotty's watch.