You should NOT power up things that have been in water.
Its not the water that kills electronics, it just causes nasty effects to electronics when power is applied. In a mild case the electrolysis between pins on boards could cause corrosion that eats away a trace, pad or pin. In a bad case the water becomes conductive enough to let currents flow where they should not and this can result in 230V mains input finding its way into a 5V supply rail and blowing up every chip connected to it.
The right step is to as quickly as possible remove power and batteries(Includes internal backup batteries), then in the near future open up the equipment and dry it out really really well. If the water brought in some dirt along with it then everything must also be cleaned first. Best is to put the PCBs into a ultrasonic cleaner, but you could just use distilled water and a toothbrush to do it, maybe add a little bit of dish soap but then rinse it off well with more clean distilled water. Dry the boards in an oven for a while to get the water out, then wash with alcohol to get the last remaining parts of water out, dry it with towels and then in the oven for some more to be sure.
Even if it powers on and works right now does not grantee it will still work 1 week later when the corrosion gets to it.
By doing this you could even save equipment that was submerged in water for days (Provided there are is electromechanical stuff in there to gum up with water and dirt).
I understand that you are a bit hesitant to open up some of the expensive equipment, but you already voided your warranty by dunking it in water. The stuff should be easy to take apart and reassemble for any competent electronics engineer, just keep track of all the screws and you can't mess it up. Laptops and tablets these days are MUCH harder to take apart than test equipment and yet even non engineers sometimes have a go at fixing them. As such an invested electronic hobbyist you have to get comfortable with taking apart your equipment since you will keep your gear for many years, far out of warranty and it will likely break at some point. Getting it repaired will cost a pretty penny, due to its age it might be a bit obsolete compared to brand new equipment at the time so it might not even make sense to repair, so you have to have fix it yourself. Also you can sometimes score broken old equipment really cheap and fix it yourself to get a very capable piece of gear without breaking the bank.
EDIT: Fixing gear yourself also teaches you a lot about how it works and shows you some design tricks that you can use elsewhere in your own projects.