Odd, my hubby and I duoed all of the bonus series on Nar Shaddaa and didn't run into any problems. I don't even remember a level 50 droid and we did ALL of the bonus series and all of the datacrons. I guess I'll have to run back over and see how we did it. I do remember some Empire characters watching us...but I guess they decided not to fight a Vanguard tank/ Scoundrel Sawbones team? It is fun to catch the imperials who accidentally wander into our base on their quests. You do have to make sure you go around their base on your way to the instance...but I'll log in when I'm home from work and see if I can find the exact route we took.
I have scouted this heroic for a few days. Just to be sure we are discussing the same thing, this quest doesn't show up until you complete all the other ones.
There are two ways to enter the Republic Research Division. One, which the green map pointers direct you to, is fully guarded by a lvl 50 imperial droid. There is no way through as a lvl 30ish player unless you stealth or rez stealth. The other way takes you through the Network Security District in the Industrial Sector. This way also has lvl 50 droids on the upper and lower levels...but you can go around them if careful. But this area has tons of lvl 30-32 gold's and silvers and is also a very active imperial area, at least on my moderately populated server.
I don't know if these areas have been changed between the times you guys did it and yesterday or what but there is obviously something I am overlooking. Just to reiterate, there are level 50 droids guarding both entrances to Lab Animals, one direction it is unavoidable, the other you can dance around it but will wade through quite a few golds, silvers and actual players to get to it.
Once you get to it, it's a piece of cake though.