Wow that sounds really fucked up ! The way you describe it… does sound like he used a Teleport hack of sorts… I had that happen to me once while I was on FT vs a predator. He was healing on the ground almost dead in front of me, I shot him and then BANG, he was somewhere else and shooting at me with a Plasma Caster while invisible, I swear to God I have 0 idea what the hell happened.
I still think it was a visual bug … the fact that I was seeing the guy crouched in the middle of nowhere healing but it was really weird and I never saw it happening again… if that is a hack… then I hope EAC manage to catch those whom are using it… if not… well… it is still a weird thing to happen… but got me laughing for a good 4 secs before I got blasted on the back with a full plasma shot which left me scared shitless and running for my life trying to get under cover so I could patch myself up… I think we ended up escaping in that match.