So hot the world (comb) is melting

Hi all - I had an unusual one today and I’m seeking other people’s experiences and tricks that you may have come across to help. I had a hive today decide it was too hot and they were thinking of getting outta there (single brood box from mid season split with 6 frames full nearly ready for second box). 90-95% of hive was out side in swarm like behaviour. I opened it up and it was so hot the comb was starting to melt off/ come away from the frames. Comb was good - heaps of honey and heaps of brood all stages and fresh eggs. I have personally never had it happen before and maybe the new location these are in is just rubbish and I need to rethink it (sheltered from the deadly western arvo sun but get full sun the rest of the day) Without going into stupid details- they started swarming and I coerced them that it was a bad idea and they head home after a few hours of chasey. I’ve put a small 3mx3m gazebo over them for shade for the next couple of days, given them a whole extra deep box and changed out the lid to one with ventilation. The other 2 hives (both double deep brood) were bearding but nothing too insane. I’ve got 10 old school ventilated bases with anti robbery trickery which I’m skeptical of using as I’ve heard pros and cons depending on who you talk to. None currently in use. What would you do in my situation with this one? Should I be doing anything else? Why just this hive? Context is: beekeeper in regional Victoria Australia. Last 2 days have been over 40 degrees and next 2 are also going to be around mid 40s (speaking celcius). Managing 34 hives across 5 properties at different stages/ size. Flow is still on with gums flowering in most of the locations. Soz about the essay Soz didn’t get a pic I was dieing of dehydration