Using Ctrl + D to exit a shell and Ctrl + C to interrupt/break off the current line is a rather strong convention. Bash does this too, and many other REPL's and shells (Ruby's irb for one).

A lot of technical folk who rely on this immediately notice when some shell doesn't do this (exiting instead of breaking of the current input line). I have this with Hbase's hbase shell. I've dropped out of that by accident dozens of times because Ctrl + C interrupts the whole shell.