I wouldn't worry about pieces leaving the ET and lodging in the system too much. I remember when I cut mine apart, someone was worried about their broken ET dipstick getting sucked into the system...and I recall looking at the pieces I had to see if that was possible...and I recall clearly that I didn't think it was. The ET has a number of chambers...and nothing big allowing a piece of cap to leave it. I'd say I'm 97% confident.
I'm so depressed. No one wants to come see me. :(
Mangofy your E46!