1) could an accident at a lab lead to another pandemic in the future? yes, certainly
2) ok then, how are we going to prevent that?
This seems much like what the world had to figure out after nuclear power became widespread; how do we keep this new technology from leading to catastrophic problems? It required international inspection, sanctions for nations who don't comply, and even big powers had to play along.
Whether this pandemic started in a lab or not, we need a system to prevent the rapid proliferation of biologically advanced research, in more and more countries, from resulting in pandemics. So, the question of whether China had a lab leak that caused this one seems irrelevant at this point; what we need to do going forwards is the same regardless.