CKS - Opa lab - opa is killed for no reason

These are the commands I ran:

wget https://github.com/open-policy-agent/opa/releases/download/v0.38.1/opa_linux_amd64
chmod +x opa_linux_amd64
./opa_linux_amd64 run &

But when I hit enter again or run any other command the process is killed, what am I doing wrong?

This is the wrong command to run – opa run is the interactive mode, and it will stop waiting for input if you do ./opa run &. Run ./opa run -s & instead.