Skills like a very well-timed freeze or shield bash can in fact give you just enough time to get out of combat long enough to have those sigils kick in. This was proved on Lavalord when a tank was timing her bash perfectly so that her sigils kicked in for one tick per bash. Lavalord = on lava.
However to answer your original question and to agree with previous answers, whilst mobs missing you stops skills being interrupted, they are not bypassed by sigils.
Re: Question about sigils
#11Belenus
Elementals
Kiyarah - 222
PiercingHeart - 193
Kiystroyer - 139
Hexi - 137
Alleviate - 135
Elementals
Kiyarah - 222
PiercingHeart - 193
Kiystroyer - 139
Hexi - 137
Alleviate - 135