Or, e.g. my preferred encoding of HTML:

    (html "abc")

This guarantees that no matter what is inside "abc" it simply can't escape into the control stream:

    (html "This is not (malicious \"boo\")")

This is just a pretty display of what would actually be these bytes:

    (4:html29:This is not (malicious "boo"))

It doesn't matter what one puts in the atom: it can't escape and damage the control stream.