Whoa! Escaping from a lab? That is a hypothesis without support. No one knows how it was introduced, but we do know that it wasn't engineered. Any naturally occurring virus could have infected humans while being studied in a lab. We'll never know.

AI isn't sentient. There's no skynet, etc. AI systems are not going to infect the internet and take over. This is science fiction for now. No one even has a reasonable approach to make AI sentient. Every attempt so far hasn't even come close.

Most AI systems are task based. You train them, given them input, and they produce results. There is no consciousness involved.