mmxbreaks

Got my first one on ticket today. Secondary security screening incoming. Not especially excited.

Any advice? Get to gate early? Be proactive with staff? Expect to be grilled?!

EDIT: It's UK (home country) to US, valid ESTA, from T3 on BA.
External company bought the ticket at obscurely high price for WT+ (company policy or something), so wondering if it's down to: 1. frequency of flying; 2. paying excessively for a 777 Prem Economy seat; 3. I've got ex-CAI and an ex-MCT TP runs incoming (neither on the "US banned list" though).