Hardrive Backup for repair?


Hello all, new to this forum and would like some help. Here's the deal... I recently spilled some liquid on my 15 inch MacBook Pro and now I am unable to turn it on. I have a warranty service where I can send my computer in for repairs. I am about 95% sure my hard drive was unaffected because my windows laptop has a slot for an additional hard drive and I was able to view some files. If I turn in the laptop with the hard drive there is no guarantee that my data will be saved by the repairs. Any suggestions on the best way I can back up or copy the files from the MacBook hard drive? I was possibly thinking I could plug it back into my windows laptop then straight out copy it to an external hard drive. If I do that and the repair company, for whatever reason, wipes the hard drive is it possible to just copy everything back onto it? I consider myself some what knowledgeable about computing but I would rather not take any chances on my data. Thanks ahead of time for any help! Oh and my last time machine back up wasn't recent enough for me to just use that.
One solution would be to send your laptop for repairs without the hard drive installed. A repair shop shouldn't need your hard drive to repair the liquid damage.
I have removed hard drives before in similar circumstances, when there was sensitive medical, or government classified data, etc.
You should ask the repair shop if that's OK for you to simply send the laptop with no hard drive installed.