Doomguy gets a note that says "Hey, mate, don't blink." Is he likely to take it into account? Probably. But how long can he go without blinking? The second he blinks, SCP-173 is snapping his neck, fancy armour or no. The MTF (Mobile Task Force) get necksnapped easy by SCP-173, and surely the Foundation would want to protect their soldiers as best as possible against this lad if need be. I will be very generous to Doomguy, who probably has never trained his blinking, and give him 30 seconds, cause gun retort would help make someone blink.
Now, can he kill SCP-173 in 30 seconds? SCP-173 is bulletproof. Rocket launcher? Maybe? He has broken through steel doors using his body as a battering ram. In any case, looking at Doomguy, he has 3 weapons that can make a mess of 173's day. Super Shotgun, Rocket Launcher, and Plasma Gun. And while they're all cool, he has a lot of weapons, and will he get to one of those three in time? I think he will get to one of them via sheer luck, but by that time, he won't have enough time to deal significant damage to -173.
SCP-173 gets my vote for durability against most of Doomguy's weapons, one-shot-kill and bloodlust.
I might reverse vote though if someone tells me that this battle will take place in Doom's Hell. Cause then Doomguy would probably also be bloodlusted.
