1) it is always a risk taking a rep into a wet or steamy environment. I have had an Explorer II get steam inside, though it should be noted that I did not grease the gaskets beforehand.
2) it is simple to grease the gaskets -- this covers the majority of the potential points of ingress for water into the case. learn how to do this and it will give you great peace of mind.
3) I have taken maaaany watches into water following greasing gaskets. No problems at all.
4) people have spoken of HeV valves. On the omegas, some HeV valves are decorative (no actual hole in case) and some actually try to follow the gen specs with an actual valve. The safest thing is to epoxy these close. I have not tried this to date, but others on the forum have. I just keep mine closed as tightly as possible and hope for the best. That being said, I am unsure if the Rolex HeVs are functional or decorative -- if someone has better knowledge of this, I'd love a PM! Maybe I'll try to take the ARF SD43 case apart during this COVID downtime..