Is that likely though?
I mean, is your department 4 people and everyone just KNOWS Jan isn't vaccinated and will quit?
Or, something like 12 people and it's Jan, Karen, and Debbie that will all leave. But, will all 3 really leave or is that just big talk. Everyone knows Debbie has a WDW addiction and needs the money.
We haven't seen any real world actual employee loss anywhere near 25%, even when it's talked up. More like 1%.
If it really is a small department, and this represents just one person leaving, which is completely valid scenario, that 1% figure is for large numbers. Then, you've already got business issues today. What if instead of a vaccine mandate, Jan wins the Power Ball? You don't think she's still coming to work after that. Not Jan, no way.
I worked in a department once where a group pooled and bought lottery tickets. They hit a big one, and 10 of 11 people in the pool quit the next week. The 11th was an executive and we think he was only in the pool to be nice, didn't need the money.
(This is also more pleasant than pretending Jan is hit by a bus. Even Jan doesn't deserve that.)
Even if you did, it's not like you quit over the vaccine mandate. It would be over the poor working hours and conditions. That's not the same as leaving because of the mandate.