Why it takes more than hours to do hunt and kill without stop?

Hunt and kill preset begins with a biofeedback scan. The hits are then run on a nominated generator. It simply can be explained as hunt-kill-hunt-kill-hunt-kill progress.

If you run scalar hunt and kill preset for the first, then it is common it will run for days continuously. Because
the scan/ run cycle will repeat until stopped OR no more hits are detected.

For common people, we have many parasites in our body, so we may have lots of hits to be be found and killed for the first time.

If you are worried that the hunt and kill preset has been running for days and you want to shorten the time. You can resettle the scan options in control tab-biofeedback scan-after scan-repeat. The default is 0 for a repeat which means it will run continuously until no more hits are found. You can set the value to 2-3, so it would only repeat 2-3 times.