I feel so naive asking this, but I really would like to better understand the specific scenario that led to being raped repeatedly "several times over months" by a colleague. Especially because it apparently happened to another female colleague by another man "in much the same way my attacker had raped me." I don't doubt FOR A MINUTE that this can happen but perhaps understanding the circumstances could provide a foc…
For all company events pair people up and make each persons' well-being the other person's responsibility. In the sense that they will share the responsiblity for reporting issues about things that happen to either of the pair, and not that they would be somehow liable for the other person's well-being. You could give people an option to anonymously "blacklist" certain partners if they don't feel safe around them, or anonymously "whitelist" certain pairings with people who they know they are comfortable around.
Bottom line, if it's not good enough to make a person's well-being their own responsibility then distribute the workload across at least one, and perhaps many other people within the organization.