Is there a good substitute for the word "scarper" in American English?
Depending on the age and ethnicity of your co-workers, "bounce" may work quite well in this context.
The urban dictionary's most popular definition (warning: potentially offensive link) lists "bounce" as:
v. to exit a location/situation.
I think it has a similar connotation to "scarper" to some groups in the US, although not all groups use this term.
'Scram!' or the old Bugs Bunny, Pig Latin version, 'Am-scray!'