﴿ فَإِمَّا نَذْهَبَنَّ بِكَ فَإِنَّا مِنْهُم مُّنتَقِمُونَ ﴾

“But whether We do [or do not] take thee away [ere thy message prevails] - verily, We shall inflict Our retribution on them;”

So if fa-immā the conditional particle in has been assimilated herein with an extra mā We take you away by making you die before chastising them then We will take vengeance on them in the Hereafter;