Corrosion is a relatively slow process. As long as the display seal is intact and the phone isn't immersed for too long, it should prevent the kind of water ingress that's immediately fatal, and you very likely can get the tools and arrest the process before it damages any functionality.
The phone I dropped in the sink had a compromised seal due to a prior drop that bent in a corner of the case - something I did actually have the tool to fix, but hadn't got to actually fixing before the drop, thinking I had time. Of course, I thought I didn't need screen protectors either, until I dropped a phone and broke a screen for the lack of one - so, while I'm apparently pretty good at learning to fix phones, my ability to learn from experience may need improvement. It was the damaged seal that let in enough water to compromise the battery, but even so it stayed working long enough for me to pull a backup before I shut it down and took it apart. They're tougher than their size and cost make them seem, and these are just 1st-gen iPhone SEs - I expect the newer ones with glued-in displays are better still at preventing moisture ingress.
(Glued-in screens are harder to work on, but not impossible; I've fixed a phone with one, for a friend. You just need a heat gun and a lot of patience, is all. Regluing a new display seems like it'd be the hardest part; my friend just needed it working enough for data recovery, but maybe next time I'll get to find out.)