Everyone messes up occassionaly. It is to teach us humility.
It's usally Jack Frost in my experience who runs around aggroing everything in sight.
Q) Why do Dominators get pets?
A) To take the blame! 
I really should do something about this signature.
The amount of times my Phantasm Army (hero side but same concept) has gotten me and us killed...
That Warwolf mission with Shadowhunter was a great example. In that instance happily it was only me. A wolfie would run off, pursude by a Phant. Two minutes later while the team is happily comtemplating the next group 10 boulders fly through the air and squishes me flat. The rest of the team are like "Wow. They don't like you"
So yeah, we all screw up. We all hit the 3 key instead of the 4, resulting in aggro city. Another speciality of mine is forgetting I've Hurricane on and attempting to jump into a mob to do a PBAOE Hold like Flash...
I wouldn't be too hard on your self. In the same situation I would have hit my AoE hold, cause with targeting time being longer on Ice Slick I'd want to make the imediate save. It happens sometimes, at least you tried
"Well, they found my diary today.
They were appropriately appalled
at the discovery of the eight victims
They're now putting it all together.
Women wrapped in silk
with one leg missing
Eight legs, one body, silk,
spider, brilliant!"
Think of it as PvP practice. 
For me the disasters *are* the game.
I've had this before as well, the plant/ AoE hold seems to have quite a low hit chance and an odd AoE shape, it's not round but a sort of rectangle.
I find I generally pop a yellow before dropping it and I still try to drop carrion creapers first as even when you hold a group they still can get an alpha strike off 
Yep, usually I have to go in close to persuade my imps to get involved, but sometimes, just when you're sizing up the opposition, they get a sudden rush of Leroy and run in and aggro the mobs whilst the team are standing around swapping buffs.
The other night something happened that shook my nerves to their core.
. 
. Now, what I did is fire off my AOE hold, & roll a miss, bringing the whole room crashing down on us & causing mass debtage 
. I KNOW what would have been better would be to have seed creepers everywhere to soak the aggro & then go for AOEs with confuse or then the holds, but it was late & I made the bad choice 
. I didn't get any come back from it, but I felt absolutley terrible & wish I could have vanished on the spot. Normally I nail this stuff 100% of the time & have a whole room or mob locked down or dealing with something else other than my team. 
. I know I'll get into some big teams again & get back to my dominating glory, but I wondered if anyone else has ever felt the FEAR like this?
. Can I come make it up with some Seeds & Creepers goodness 
?
I joined a team of people I've just started teaming with & become friends with. It's a great set of characters to team with & all good players. Usually the mobs get locked down, & then crazy buffage happens & next all the enemies are face planted thinking "ZOMG! Which n00b aggro'd the heroes????"
On this occasion, the team was full & we were taking on some relentless level 40+ CoT in an Oranbega mission. As we were getting ready for the next, very large & dangerous mob & setting up to attack, someone got spotted by one lone CoT & started getting fired at. I thought "uh-oh" best lay something down here before everything comes piling in
Thing is, 'cos it's the worse mess up I made so far on my Dom' & he's normally great holding mobs, bosses & Hero's etc, I found I suddenly have the FEAR the next few times I've teamed on big teams & missions. Now I feel like the Maverick of Domination
Sorry to the team