This encounter proved extremely brutal for my players as all of the monsters benefitted from the enhanced damage to Thunder or Lightning keyword powers while none of theirs did. As I mentioned above, none of them had played the previous 2 sessions of the lower floors so I as quite happy to drain some of their resources prior to next sessions finale. I did make a conscious decision to enforce the elementals 2-square sensing of the party though and gave the players the chance to avoid detection whenever a hurler or votex moved within range. I also decided that the hurlers would rotate anti-clockise and the vortices clockwise around the staircase.
I half expected some of the party to make a dash for the two bedrooms and then become temporarily trapped once one or two elementals detected them but the party as a whole chose to remain in the section between the small stairs they had come up and the central staircase.
Our FLGS (Tabletop Tyrants) is closed next Wednesday evening so we dont have a game next week but have agreed to run our usual 2 sessions for the series finale the following week on what should be the session 0 of the next season.