Tom Holland's musing about the "Instant Kill" function came when he was asked at the London premiere of Avengers: Infinity War HeyUGuys why Spider-Man doesn't use that feature on Thanos, who is threatening to kill half the universe against Thanos. Keeping in mind that Thanos is one of the universe's most powerful beings even without the Infinity Stones, and thus Holland is likely correct that "Instant Kill" wouldn't work on the Mad Titan, as seen in HeyUGuys' video, the actor believes that "Instant Kill" is actually just an EMP device. That would certainly come in handy if you want to shut down any phones, computers and even cars before engaging with the enemy, but given how Spidey's eyes turned black and red when that function was triggered, I can't help but think that Holland is wrong on this one. With a look like that, it definitely seems that "Instant Kill" is indeed lethal, but I'm sure Tony Stark could still outfit the Spider-suit with an EMP device if Peter wanted one.