Although the time frame seems off (the usual scan time for an iPhone is three minutes), a consistent reboot cycle still does sound like a kernel panic. I would manually go in and verify whether there are any panic logs available; a three minute cycle is long enough for that, so your 5-6 minute cycle should be plenty of time.
The procedure for locating them is documented in @flannelist's excellent wiki page.
[[iPhone Kernel Panics|iPhone Kernel Panics - iFixit]]
Use the guide to find the logs and assuming there are any available, either screenshot or copy/paste the first page of the most recent one then come on back here and add it to your question.
[guide|21499|Adding images to an existing question - iFixit Repair Guide]
If, on the other hand, you don't find any there, come on back and tell us that and we'll see if we can figure out what to do next.