I see, yes runboost might work indeed.
Anyways I went on 'Create a server' to have a look at this map and I found out/remembered a few things :
1) mind the noclip, it's just to show you that I thought that that was the house you guys were talking about, so I went towards the roof of the house in and to my surprise, I ended up being tele'd to 2)
3) I have seen a few players actually managing to get there, but don't know how they got there, just saw how they were the last human of the round (again it's just me with noclip to show you guys) but I seen it on v2.
4) You can get there by longjumping from the other one that you climb by the ladder, obviously it's not so easy on EH with sv_airaccelerate set to 7 (on default it is 10 so it might've been slightly easier for me to get there)
5) This is the 'edge' on Sour's screen, and there is actually something on the other side (after taking this screen I noclipped to get in there to see if there's anything in there, nothing except that fire-water thingy in Sour's screen)
Also if you guys didn't know already, there are beams on several places in the map, all that insta kill you (like in screenshot 1) :>