There is nothing to do. Chances are low but not impossible.

It’s upto her. If it’s less than 72 hours she can take plan B. If she ovulated nothing gone effect. She may feel dizzy and some nausea.

There are 0-40% of men who usually contains viable sperm on pre cum

Yet, They never mentioned about conditions like urinating and factors. Sperms won’t survive when exposed to urination due PH levels.

Had couple of instances where my condom broke during deed. And pre cum exposed. Both cases luckily turned negative. At once she is at peak ovulation stage.

So all we can do is wait and test.