Direct Question: T3 Keys.

[Murdos]

So, managed to wrap up everything for my Boltor Prime except the Blueprint, and I want to grind out T3 Mobile Defense to do that, because paying 120+ Platinum for a damn BP kind of rankles my extremely poor self.

Therein, lies the issue.

Where the heck do I get T3 keys easiest? Is it only from T2 void missions?

[Angius]

Tier 3 Survivals, like those on Pluto or Eris.

 

Check on Wiki.

[Murdos]

Thanks, I couldn't find it until you mentioned a specific planet; which had a nice list of rewards linked within.

Appreciate it. 

[Darzk]

Eris and Sedna both have Corpus survivals that start at tier 3, but are only at level 15. Very few heavies and none of the specialty units will spawn by the 15 min mark, which is 100% chance for a T2 or T3 key.

[xkillo32]

gl grinding

i just bought the t3 md keys

after 25 i finally got it...

[heeho]

Tier 3 survivals only have a 50% chance of dropping a T3 tower key at the 15min mark...You will get T2 keys the other half of the time... 

If you're really unlucky you might have to do 5-10 rounds of 15mins survivals to get the key you want, which can be anywhere from 1 hours to 2 hours. Its really highly inefficient...

You are better off trading for the keys in the forums or trade chat, or jumping into recruiting channel to look for the key runs you want.