JavaScript event loop does NOT “run to completion”

According to MDN, messages in the JavaScript event loop “run to completion”.
(https://developer.mozilla.org/docs/Web/JavaScript/Event_loop#run-to-completion)

But I have created a case where this does not seem to happen.

abortController1 = new AbortController()
abortController2 = new AbortController()

abortController1.signal.addEventListener("abort", () =>
{
    console.log("abort 1 start")
    abortController2.abort()
    console.log("abort 1 end")
})

abortController2.signal.addEventListener("abort", () =>
{
    console.log("abort 2")
})

abortController1.abort()

Output:

abort 1 start
abort 2
abort 1 end

I was expecting to see this output:

abort 1 start
abort 1 end
abort 2

Can someone please explain what’s going on here?