Astarion: I was RIGHT THERE - Baldur's Gate 3 

One of Astarion's best dialogue after being killed by the solar lance at Rosymorn Monastery. Got revived by Withers.
HOW TO GET THIS INTERACTION: In the githyanki creche, (follow Lae'zel personal quest about finding a cure) get the legendary 'Blood of Lathander' weapon by stealing it (don't use the Dawnsmaster crest that you get in the monastery puzzle), you'll activate a trap and if you don't manage to get Astarion outside the creche in 4 turns he will die. You can revive companions in camp by talking to withers.
After being revived just talk to him at camp.