I was playing an intel mission with someone and it had reflect 3 % warp damage.  In it i used constrict once or twice without thinking and my hp would shoot down, then I killed an enemy with 4k hp left with it and the crit said somewehre around 629942 damage(I was recording). This killed me instantly.

Also now that i'm thinking about this the damage amount on reflect seemed applified in that mission.  The damage #s would say 10k damage and the enemy would lose like 2k hp.  I'm starting to think it was basing the damage I was taking off the incorrect value of pre mitigation damage(also multiplayer enemies seem to just take less damage because multiplayer).

Reflect% is also just a bad mechanic because the easier of a mission you do the more brutal it is and that is just backwards.