Is this plane perforated?

Everyone's familiar with the things you don't want to hear on a plane.  Things like, "We seem to be having a problem with the left engine," and "y'all should probably put on your oxygen masks now."

But to encounter something you don't want to see on a plane is much less common.  

No flight gates (or limits on carry-on items) in the domestic terminal of Jomo Kenyatta.

Approaching the plane for boarding...

And in case you need a clearer view:

Cut here.

YES, it says "Cut here in case of emergency."  

Cut it why?  With what?  Giant scissors?  A machete?  Is this plane perforated?!

If someone can tell me what exactly this all means, I'd be very appreciative.  We never got any clarification, as the plane never left the ground.  Turns out, there was a problem with the left engine and we were relegated to wait several hours in the terminal for the next available vessel.