Risk taking is often associated with Ne. You have to be aware of risks and why you are taking them. It can be a leap of faith into the unknown, or uncertainty. So risk can (must !) be evaluated. Now, Si doms think a lot about security and safety unlike E-Ps who have a tendency to impulsivity. In general SLI will not risk anything, they have to master what they are doing, be aware of stuff that could go wrong. So in a new situation the first think they'll think about is safety and security. They are very good in emergency situations (like all Ips). There is an aspect of Si dom that is not talked about that often, it's the status awareness of objects not only their own body but also others bodies, biological entities and object (if blocked with Te) or emotional state (if blocked with Fe).
As a reminder some definitions (Gulenko) :
Si+ Sensation of Comfort : Adjusting the environment to make yourself (and/or others) as comfortable as you can. Make your territory autonomous. (SLI) ((little spoiler)
BIll from the Last of Us is SLI imho)
Si- Sensation of Discomfort : Treatments of malady or resolution of everyday discomfort (SEI). [I find this def. quite superficial]
So there is this notion that I call status/ data acquisition - (diagnosis) - Status/restoration i.e. knowing the natural state of things and being able to restore (or repair) them to their original (healthy) state.
With that said, the human brain is fully mature around age 24. Before that anthropological brain maturity, the will to take risks is higher (natural drive to experience life due to various factors (hormones etc..)) and that's obviously true for everyone even if some temperaments are more risk takers than others.