Will we see Malchus in heaven? Probably. How do we know his name is Malchus? John tells us 50 years later which might indicate that he was part of the early church.
This is the only external wound that Jesus heals.
Shall we strike with the sword? The disciples wanted to defend Jesus and themselves. I’m sure they were confused by Jesus’ lack of defense or attempt to escape.
John 18:10 tells us that Peter is the one who strikes with his sword. Perhaps the others are asking and Peter is acting. Why don’t Matt, Mark and Luke mention Peter? John writes after the destruction of Jerusalem. The others wrote before. Maybe it would have caused harm to Peter.
Jesus had just told Peter that he would deny Him, but here we see Peter standing up for Jesus. Luke points out that it is just a piece of the right ear. Perhaps this shows us that by ourselves we can accomplish nothing - except to make matters worse.
Matt records that all those who live by the sword, die by the sword. If you think that is the way you will be protected, then you are wrong. Jesus tells Peter to put away the sword. It is part of the need of the suffering Messiah. He had the power to escape but the purpose to stay.