2.18 I'd like to "swap" quickly from one account to another in MPE/iX. How can I do this and still maintain all the security I've got in my original account?

If you are changing to a different account only to make it easier to type filenames and not to change security, logon UDCs or user ID, then you might try using the CHDIR command

:CHDIR /SYS/PUB

This changes your current working directory from where it was (probably your logon group and logon account) to PUB.SYS. Note: POSIX syntax is necessary to CHDIR to an MPE group. It's a lot faster than running a second level CI.