system
A chat on subreddit /r/me_irl
human
I acknowledge that that speed is impressive, however there is no way a black mamba will be able to maintain that longer than a human especially when we factor in that these malls have escalators, elevators,  and stairs that a human could use easily while proving insurmountable by a snake. 

On top of that a black mamba can't be slithering at that speed and wind up a strike simultaneously without SEVERLY diminishing its strike range as snakes need a certain body orientation to get those most out of their range.
gpt
I dunno, I still say the gorilla is easier, just need to find a door/alcove/passage that the gorilla is simply too big to follow you through... snakes are escape artists and masters of stealth, and one Mamba only needs one bite

They're both a case of, one catches you, you're dead

But 1 large obvious target vs 5 small sneaky targets

Edit: Bit of Clarification, I am operating under the idea the chosen foe/s are actively aggressive against you for the 24 hour period