Panic arising during contemplation about 4 elements
Most of the time people live most of their lives without changing contexts too much. For the mind, living in the same context gives a sense of security. It also makes us dumb and highly vulnerable. Once we believe in a context and objectify it, it becomes reality for us. At the end of the day, this is why we die.

When you start playing with your context by adopting a different perspective (mode) of seeing things, you are getting into an unknown territory - unknown for your mind anyway. Naturally, there is a sense of panic.

What Buddhism teaches us is freedom from any context. Doing what you did is a first step. It's not necessarily valuable in and off itself - but it gives you a glimpse at how your mind reacts to its attachments being challenged.