He gave me back the battery to put back in on the Thursday if I want to, or just bring everything back down and have him do everything. And I'm still researching if I can even disassemble the computer by myself. I'm going through the steps and see if its possible, but I don't honestly think I can do it.
If you don't think you can do it (disassemble & dry out the laptop)...then ask the repair guy to do it (of course he may charge you).
At this point your laptop may or may not be a goner. If we think positive...and assume that it's NOT a goner...then reinstalling the battery on Thursday (and turning the computer on) may trash what may currently be an operational computer.
If there is liquid still in the computer on Thursday (when you try to power it on)...it may short-out right away...or if the computer works ok initially...when you go to move or tilt the computer during normal use or transport...there may be liquid in the cracks, crevices, or just unseen areas which may migrate to an electrified area of the laptop...and then things will short-out...and then your computer will be a goner.
Basically the conservative approach is best. Completely disassembling the computer (not the display part) and making sure everything is dry (this involves more than removing the HD, ram, and battery) is the way to go. Sure...maybe by Thursday all the liquid may have completely evaporated...and trying to power it on will do no harm. But if there is still liquid in there, and you power it on...are you ready to make a $700+ mistake???
Remember...the repair guy wins if you destroy your laptop...because he makes money repairing it. Maybe he feels that by Thursday all of the liquid will be dry...but without removing the logic board to see...you will never know before powering it on.
Also consider that some of us here at Mac-Forums may be much more experienced than the repair guy you visited (not saying he's not a good/competent repair guy...just that he may be very busy to disassemble your laptop & dry it out unless you actually request it). And remember we have no financial motives...we just want to help.
Good luck what you decide to do,
- Nick