I can't stop you, but face value looking at "better indoor surveying equipment" that does not sound like a good idea.

Indoor surveying is either beacon-based (if exists, MTR likely won't expose the beacon implementation details) or rangefinder-based (potentially expensive equipment; LIDAR, laser, or what technology?) There's also a concern that the crowd may interfere with measurement.

Also see https://www.openstreetmap.org/note/2087499

But yes if you can somehow find a way to do this cheaply and conveniently then you can deduce exact range, and use dead-reckoning to add towards the real location, etc.