I'm not the parent but if you know you want to merge a PR "within a few seconds" then you're likely to be merging in bad changes.

If you had left it at know you want to reject a PR within a few seconds, that'd be fine.

Although with safety critical systems I'd probably want each contributor to have some experience in the field too.

Sounds like you misunderstood. They didn't say they are merging PRs after a few seconds. Just that the difference between a good one and a bad is often obvious after a few seconds. Edit: typos

Exactly, every PR starts with:

1. What’s the goal of this PR and how does it further our project’s goals?

2. Is this vaguely the correct implementation?

Evaluating those two takes a few seconds. Beyond that, yes it takes a while to review and merge even a few line diff.

I'm not sure there are many ways to interpret "I know whether I want to merge a PR within a few seconds".

Yet I also agree with GP.

"*WANT* to close or *WANT* to merge". Not WILL close or WILL merge.

You look at the PR and you know just by looking at it for a few seconds if it looks off or not.

Looks off -> "Want to close"

Write a polite response and close the issue.

Doesn't look off -> "Want to merge"

If we want to merge it, then of course you look at it more closely. Or label it and move on with the triage.