I have a question

For example. Imagine, BTC hits 100k and the sell-offs begin. Hypothetically there are 100 people selling and only 90 buying. That difference of 10 of those who are selling, who are they selling those BTC to? The same with any action. If I start selling all my shares, who do I sell them to? Who buys them for me? And if there isn't a person instantly buying it from me, how is that possible? If BTC reaches 100k there may be more people selling than buying, so who will buy them from me? Who do I sell it to?