Some of you might think, ''wtf this is common sense, just kill the mobs and engage the boss'', your wrong.
Currently this instance is bugged bigtime on the ptr, causing you to dc after killing some mobs/starting some encounters, being booted back to char selection screen and having the whole instance reset.
This has most probably to do with the interaction Jaina/Sylvannas have to make after killing those mob
This guide will show you what to touch and which mobs to dodge, and most of all, how to reach Ick and kill him.
When you enter ignore the first 2 mobs, go around the right, into the water
hug the right hand side, kill the 4 skeletons, avoid the 2 guys on proto drakes and shazam your standing infront of the boss.
Run to the very end of the instance, the large skele mobs are safe to kill, as are the necromancers.
You will see the end boss of the instance, Tyrannus, on a giant ramp, attack him and kill him (the rider, not the mount).
This boss is really incredibly easy and should be a breeze even with non-premade characters
If you have done this you can go back to Ick's room and engage him, it is a very funy fight but im not going to spoil much for now.
Note that if you wipe the entire instance will reset, so try engaging stuff your not to sure about with 4/5 and leaving one member left ooc (you can enter the instance again as long as one member is left alive)
That is all! happy testing folks