In a survival situation a saw is better. You can find them to fit any size survival kit and even when cutting large wood, it will expend less energy. You don't need large size wood or huge amounts of wood for survival anyway, a small fire is more efficient, safer and manageable. I would not recommend any multi tool or pocket knife that does not include a saw blade.

However, a tool is just a tool, and the dangerous part, even in Doug's words, is the user. Fatigue and lack of experience and confidence can lead to trouble. Any tool can be dangerous, even a screw driver. You use what you are comfortable using, and you use what you have in the situation. If you lack experience chopping and splitting wood you can always learn. I would recommend the methods taught in Boy Scouts. They are safe, even for kids, and I have taught many kids to chop wood without ever having a single accident or injury. If you learn it, and you end up needing to use an axe or hatchet, then you are less likely to injure yourself. Knowledge and practice are a big help.