Picked up EMF Detector Today - Been Beeping Off & On Since i got it - This is Scary!

Today i picked up a Meterk EMF Tester -" Electromagnetic Field Tester" It was left on at the factory and was beeping today when i picked it up from the Post Office. The Clerk was concerned and said they thought it might be a b*mb or something, because it was beeping off and on since it got there. I took it out of the package to ease their concerns. lol
Heres what doesn't ease my concerns though, The alarm is still "Beeping" has been picking up Dangerous levels of EMF frequencies, even when not close to electronics.

How to measure EMF and Radiation
http://www.magneticsciences.com/EMF-health/

Model of EMF Detector used in podcast
https://www.amazon.com/dp/B0754VVW4W?psc=1