There are scrolls of protection from petrification BUT...
the best way to do it is summoning some monster that are INMUNE to petrification (like skeletons, ghasts etc). The best choice is the clerics spell "raise dead", cause raises lots of them and they last for 8 hours.
Once you summon them, send them in front and kill the basilisk with range weapons
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"Let my spells do the dirty work" Ertai, High Sorceror of the Holy Flame