What constitutes as a restrictive or nonrestrictive?

I'm struggling with trying to figure out whether or not this sentence needs a comma before "only."

"He stopped running, only to grab a log from a stack of firewood and launch it at me."

On one hand, the comma and natural pause sounds more natural to me but I'm not sure if "only to grab a log from a stack of firewood and launch it at me" constitutes as restrictive? It is also a dependent clause and therefore wouldn't need the comma after "only," right?

I'm very unsure of what to do here.

Solution 1:

He stopped A, only to B. This is a reasonably common construction in narratives. It does not mean he stopped A for the sole purpose of doing B. It means that he stopped A which was bad in some way, and then began doing B which was also bad.

He stopped running (so I thought I was safe), only to grab a log etc (when I found I wasn't safe).

The tenant in the room above stopped dragging furniture (which was keeping me awake) only to start dancing (which was just as noisy).

The reader is led to think briefly that a problem is solved, but then discovers that a new problem has arisen.

If the comma is left out it would mean that the only reason for stopping A was to B.