Did Dolohov go into the room with Chloe? Based on his conversation with Barty, it looks like he visited the center room (with HG), the Death room (with PP/SAP/Hector) and the Time room (with HL/JFF) but that he never went into the room with RW/LL/Arista or the room with Chloe before Barty said he was coming back.
I actually did interpret what happened as Barty maybe putting Chloe out of her misery, not out of spite but out of kidnness? Although maybe not, he may simply have getting information out of her and found out about the kids and then she died on her own.
I am so, so curious as to why he willingly left with Tosha at that point, though, despite knowing Arista and Hector were still somewhere in the DoM!