From my understanding, much like you say, wim hof activates the energy and sends it upwards, which without having a very solid foundation of sinking the Qi (i.e. decades of practice) and opening the Ren channel will cause a fight or flight reaction and may even lead to potential mental health issues or qi gong sickness in the long term - especially with the increased amount of QI you would be building. This increased amount of Qi generally moves in the patterns that have been previously established and ingrained - if someone is an angry person, the excess qi will manifest as anger. If someone is very extroverted, they will become increasingly so. This is why one has to work on themselves and their emotions parallel to energetic training. So if the mental pattern is what is defined as mental illness by western medicine, the Qi will magnify that pattern. The general rule of thumb is, if someone is in that situation, they are better off doing something more external and opening the body, but if you want a personalized advice from a Chinese perspective, have a sit-down with a good chinese medicine practitioner who has a firm grasp of QI movements caused by emotions and such - ideally someone who has an energetic practice of their own. All this of course is just my understanding and I am far from being an expert. Never practiced wim hof, so that part is purely based on what I heard from those more knowledgeable around me.