The locators are set to determine the part length and he has soloed the tracks he wants so nothing else is included so export audio mixdown would certainly give this result (make sure no master bus FX are active unless you want them included)
Actually I was thinking RIP was introduced in 8.5 but on checking it was in C8 already so Prock is probably spot on. You just need to set the Render settings first to mixdown to one track as by default it’s set to keep them separate.