the only timeloss is the allied reinforcements dialogue

if zhao yun is played, there is no intro dialogue and you will get yan rou's encounter dialogue, which is fine since this gives you just enough time to reach cao hong's ambush and defeat him zhao yun's defending the main camp dialogue is also skipped

if cao zhen's pathway ambush is triggered as ma su walks through the boulder ambush trigger, it can be avoided, which results in a softlock