As Nike would say “Just do it”.
Some people leave the table but I always inject where I am. The table is far more hygienic than the bathroom.
If you have a friend or partner, you can get them to dominate the conversation/distract everyone else in the time it takes to get your pen out, dial up the dose and stab yourself.
I always went for the tummy area and wore separates so could life my sweater/pull my shirt open without exposing too much bright white flesh.