The kid took it to the N'th level..
But the idea of a small pen laser for the SHTF kit or even the weekend hunter/backpacker/hiker is some we could all use..
A 150mv pocket tool, good for a fire starter or signaling tool.
If you do "burning laser" on youtube, there are bunches of examples of how to make one.
https://www.youtube.com/watch?v=bQWx-7lH8ec