I've added arrows to indicate the movement of Mr. Red and Mr. Yellow, moving to attack Ahmet. Mr. Green continues to load his crossbow, while Mr. Pink falls back. Nothing else changes.
Mr. Red misses Ahmet, but Mr. Yellow hits with a natural 20 (and the DM has some luck, finally). The flail does 2-8 damage; I roll a 7, +1 for strength, and Ahmet takes 16 damage. This, I'm certain, will stun. As he falls back, Andrej only has to put out a hand to be sure Ahmet doesn't fall into the hole, but instead staggers to hex 0606 - I'm going to be generous and say this happens with no-movement cost.
Andrej, you're free to move. Whomever is next (Janos, unless he wants to change with Lukas) will take Andrej's present position the following round.