Yes. The initial stage is just to clear the tube and operator. The second stage is the more powerful one that needs to make its way to the target at a high velocity.Yeah. I realized that the NLAW has the pop like propulsion as well and did a careful comparison between the two. The Javelin’s fins (or wings?) are more obviously expanded immediately at launch though. The NLAW one isn’t as obvious.
Also, why would firing a single stage rocket be dangerous? Is it due to the back blast pressure?
With a single stage you've got the big rocket firing straight away. The back blast is MUCH larger, as many Syrian Jihadi has found out.