undefined local variable exits rdebug

[karatedog]

Is it a normal behavior that rdebug exits to prompt when encountering an undefined variable?

I have a one-liner ruby script.
$ rdebug rdebug_test.rb
/home/karatedog/work/projects/ruby_stuff/mandelbrot/rdebug_test.rb:1
puts nonexistent_variable
(rdb:1) n
/home/karatedog/work/projects/ruby_stuff/mandelbrot/rdebug_test.rb:1:in <top (required)>' /var/lib/gems/1.9.1/gems/ruby-debug19-0.11.6/bin/rdebug:125:indebug_load'
/var/lib/gems/1.9.1/gems/ruby-debug19-0.11.6/bin/rdebug:125:in debug_program' /var/lib/gems/1.9.1/gems/ruby-debug19-0.11.6/bin/rdebug:412:in<top (required)>'
/var/lib/gems/1.9.1/bin/rdebug:19:in load' /var/lib/gems/1.9.1/bin/rdebug:19:in

'
Uncaught exception: undefined local variable or method `nonexistent_variable' for main:Object

I'm not a ruby guru, did I miss something?