It seems no matter what class I make I end up dying once its time to grind there. I can take out 2-3 of the mobs on the 1st floor at lvl 54-58ish but they all seem to aggro towards me from across the room and by the time I'm done killing them all they start to spawn again and just eventually wear me down.
You should learn the mobs agroo pattern and social range, all mobs in TOI are agressive.
I never had problems in TOI with the Blade Dancer I leved to by my Iss, you just need to pick the enemies wisely and look for the social agroo they have.
seems u don't kill fast enough , try a lower floor or don't go between the mobs, stay in a safe spot and lure few of them at the time , run to the safe spot ,kill and repeat, it will take longer but its safer , dont leave your char afk even in the safe spots, other players run with the mobs into the safe place cause they can't handle them and once the mobs are done with them they will aggro you :);
and maybe u use newbie buffs, go aden buy iss buffs,after 30 mins soe and port back toi, its cheap now with the invasion of iss'ers and you get your money back after kiling 4-5 mobs , it's worth it .
hope it helped.
i've done Toi and 2 melee classes and 3 ranged.
just gotta get ISS buffs (dunno if you have been getting em) and you shouldn't have a problem.
with melee its a bit more difficult seeing as you gotta watch your health and maybe drag a couple out to avoid over aggro.
(but that also depends on which melee class you're making, my gladiator had no problems)
It's doable even with newbie buffs, but I'm probably partial since I'm playing a summoner sub, with a SWS teammate, and it's a rather OP combination...
But for solo players, Iss/mentor buffs are the best bet to be able to survive without too much trouble.