Afraid mobs and Ice/Traps- Advice.

I have a 38 ice/traps that I've been leveling up pretty much entirely on TF/SFs with a bit of soloing. She's been an effective and fun character to play all this time, and I've liked the utility of the slows and holds in ice/, especially since IOing out at 30 and having the hold procs.

However, last night I duoed with a friend on his Night Widow, and every single spawn kept fleeing in every direction possible once I'd opened with mortar/poison trap/caltrops/ice storm, and it got us killed a few times as the enemies weren't being debuffed and our AOEs were ineffective. He found it really aggravating and commented 'brutes must hate you'. Now, I've never seen this happen before on this character, presumably because I've been on TF teams all the time with a mezzer and/or a tank/brute using taunt or a taunt aura.

How can I mitigate this? The slows of caltrops and ice didn't seem to help at all (but I haven't got either slotted for slow- caltrops has a dmg proc, and ice storm has posi's blast and the slow dmg proc).

I tried web nade and freeze ray to lock mobs down for my DOTs, but for a full size spawn of 8-10 mobs by the time I had them all locked down my teammate had killed them all. So I just resorted to blasting and being a manuevers/ffg defence buffer.

I intend to take web envelope at 44 (after scorpion shield at 41 which I would say is more urgent) but am I stuck with scattering mobs until then or is there something I'm missing about how to keep them together?

A (Trapper + Fortunata/NW ) should have both of you soft-capped and runners shouldn't be an issue at all. Just let them run and keep on killing forward into more targets.

PGT can lock them down for a very short period of time, especially of slotted with something equivalent to a full lockdown set.
Additionally, You can add hold procs to several powers, especially on a Traps/Ice or Ice/Traps.
Lastly, you can both take immobilizes at 41, if you must.

However, yes, there is an in-between where you don't kill fast enough and even stacked slows aren't enough and some mobs run away with very low health. I never really had major problems with this, unless I was the only high-level on the team and my team-mates were very low level. With the just wrong combination of levels and team-mates, it can indeed be a pain, but that was always the exception for myself, not the rule.

Caltrops and the rain powers is what is causing the mobs to scatter..

Poison gas trap + Lockdown chance for hold proc will solve a lot of your problems. My fire/traps corruptor has it in his PGT and he gets bosses pretty frequently and Lt's/minions get locked down for quite a while. Also, use caltrops sparingly - I use them for area denial more than a slow - throw them on the far side of the group you are fighting, towards the new groups and that will make them run the OTHER way.

The problem with caltrops is the patch isn't that huge and the slow is iffy - depending on map geometry many NPC's can jump out of it far more easily than they should but if you throw it where you don't want them to go, then hit them with ice storm you will drive them back into your group. You should be stealthing into the middle of the group or slightly on the far side, dropping PGT + acid mortar, then throwing out your AoE attacks and caltrops as needed.

Everyone else had given good advice here. Only thing I would add is that you also want to get the Devastation chance for hold proc into acid mortar in addition to the Lock Down proc in PGT. Between those two I have no problem keeping two full spawns stationary long enough for Rain of Fire to do it's thing on my Fire/Traps corr.