It seems like a weird misunderstanding and latency delays. Here comes how, if you look at at 0:24 (shown in picture) he threw the grenade and following him to 0:27 you can hear m60 shots continuously. Which makes sense the grenade probably got hit to the wall.
Here his second grenade can be seen in screen which wasn't exploded at all, and here he gets hit by Kripton's first grenade.
Final conclusion is, because of delays and VC:MP/server sync he was about to get knocked by the grenade but before he faced it, the shotgun bullets from Cool4 hit him as his animations are clear
Because of bad sync and delays, it seemed like a suspicious clip no doubt. But if kripton was hp hacking he wouldn't had get knocked by Cool4 and get killed. Delays cause such issues more often. I believe the pings were not stable and low while all these happened. So yeah latency and delays caused such incident.