So, there is a way to temporarily disable the Performer (and similar 020/030 upgrades for 68000 Macs).
After the chime hold Interrupt on the Programmer's Switch, then quickly press Reset. After the second chime release Interrupt. The upgrade is disabled until the next boot.
MacsBug doesn't work with the Performer enabled. When installed on System 6.0.8, MacsBug pops up during boot with "Illegal Instruction at 000118C2". Keyboard doesn't work so you can't exit it.
After the chime hold Interrupt on the Programmer's Switch, then quickly press Reset. After the second chime release Interrupt. The upgrade is disabled until the next boot.
MacsBug doesn't work with the Performer enabled. When installed on System 6.0.8, MacsBug pops up during boot with "Illegal Instruction at 000118C2". Keyboard doesn't work so you can't exit it.
