Container escapes exist. Now the question is whether the attacker has exploited it or not, and what the risk is.

Are you holding millions of dollars in crypto/sensitive data? Better assume the machine and data is compromised and plan accordingly.

Is this your toy server for some low-value things where nothing bad can happen besides a bit of embarrassment even if you do get hit by a container escape zero-day? You're probably fine.

This attack is just a large-scale automated attack designed to mine cryptocurrency; it's unlikely any human ever actually logged into your server. So cleaning up the container is most likely fine.