I didn't specify any specific encounter or I would have specified a specific encounter. How about you assume I meant....any encounter "without the rules for protection".
To that end you've given two sample encounters the second of which includes a pretty good answer to my very open ended question, allow me to paraphrase so it actually makes sense relative to the question.
"MMA fighters are repeatedly trained to engage opponents, this is a dangerous habit because in some situations where they don't have the rules to protect them, the reflex of engaging opponents is detrimental to rapid disengagement and escape from the conflict".
Most MMA fighters are well trained in Nike-do and do not engage in random engagements of either the marital or martial type. Others of us, the door staff, the police officers etc have little choice and have to stop around, but hey ho, it's a living.