To use the Infiltrator class right, you have to be a good flanker
You need all abilities unlocked to be a beastly INFI, so 11 points are mandatory before class becomes ridiculous
I started this BETA as TACT, I'm very good @ grabbing locations for my team.
I leveled up quickly due to it (S&M really did help a metric fuck-ton)
Just kept playing on TACT, and hoarding points to unlock INF
Once I had enough, I started unlocking stuff for it
Unlimited Sprint Speed/Boost makes you the fastest thing out there, use that to your advantage
If a choke point is created, don't disguise yourself and run through there hoping the other team won't fire on you, be smart and flank, run around the backside and come up behind them, have proximity mines, and lay them behind you, they will be your blockers, so you don't get back stabbed or owned, + get you 1-2 extra kills
Now just melee to your hearts desire (you don't lose your disguise), I did this, and earned a 5 melee kill streak (4 brutal, 1 regular), with-in 35 seconds, then 2 dudes ran over my mines and got 2 more kills
Then I shotty'd 3 others who were running up through stairs and corridors, so 10 kill streak was achieved within 2 minutes of me being smart and assessing the situation and just flanking them
Disguised INFI should always try to melee first, you have the speed/stamina, + you don't lose the disguise, once you shoot, 1-2 seconds your disguise starts to flicker and goes away and then you wait for cool down
TACT varies on each side, if you are ISA TACT, first thing you do in game is to run to spawn location B, the one in the middle, near the doors that leads to the dam, then back track back to A as quickly as possible closest to the ISA S&D, get that location, 100 points achieved
Drop 1 of your sentry bots here, he will patrol, protect the area, + if it blows up due to enemy fire, you will know your bots destroyed, signaling you that enemies near your base
Now run up the stairs next to the spawn A, then up the stairs to the hallway which merges with the HGH complex on the right
Pop S&M, watch them blue circles start giving away the enemies locations, and start chasing them or hold back and have the upper hand by being in ADS waiting for them to turn the corner
If HGH TACT, get that spawn C that is close to your S&D, it is vital, it can help flush your team right into the fray if it's C&H or Defending your S&D
Try your best to get the middle one to really control the map
It helps out during Assassination on both sides, if HGH assassination targeted, team can become a wall and keep ISA at bay, if ISA targeted, you have cut the map to 1/3rd of the ISA to hide
Only time you want Spawn A closest to ISA S&D, is during ISA S&D, you can flank the whole side there and overtake the team
So ISA A & B spawn locations mandatory, HGH B & C spawn locations mandatory
Unlock the 1 point pistol for TACT, it can save your ass
I'm just gonna abbreviate the classes
INFI
TACT
MEDI
ENGI
MRKS
INFI:
Shotty or the 2 point gun
Silent Footsteps or Armor, preference up to you
Proximity Mines
All abilities fully upgraded (11 points)
TACT:
SMG or try to get the M82 (cost you 5 points)
Armor/Extra Ammo
Grenades
All abilities fully upgraded (11 points)
Pistol/Revolver (Revolver not easy, practice)
3rd class I'll start working on is Medic, I was a full medic in closed BETA, but tried these 2 before to see why they were so broken
4th will be Marksman, 5th Engineer
Pro-Tip: Sometimes dying to reset you abilities = better than waiting for cool down. TACT, get 4-6 kills, S&M taking it's sweet time, die, new S&M up for team + new Bot to call out