Same IP, different PC

[car]

Hi all,
I recently found that All the PCs in my company are now accessed internet with the same IP. What would happen if someone who know my website click on the Google ads there? then what I should do to get out if there is any trouble concerning this problem?

Note that I only log into my Adsense account from my own computer.

Could anyone here tell me how Google detects and handles invalid clicks? Then what are the best practices to protect Adsense account.

My most sincerely thanks to all the reply and help.

I treasure your time.