Corrected entry: When Spock mind melds with Valeris, you hear a heartbeat. Whose heartbeat is this? It is specifically stated in the original series that Vulcan hearts beat almost twice as fast as humans. It is, however, never established that Vulcan metabolic functions slow during a mind meld, due to conscious physical control or otherwise.
Grumpy Scot
3rd Jun 2003
Star Trek VI: The Undiscovered Country (1991)
Correction: The heartbeat is almost certainly not diegetic.
Correction: It was "never established that Vulcan metabolic functions slow during a mind meld." Not "it was established that they do not." If something is not established one way or the other, then there is no contradiction and therefore no error.